Citation
Contributions toward a monograph of the scolytid beetles

Material Information

Title:
Contributions toward a monograph of the scolytid beetles
Creator:
Hopkins, A. D ( Andrew Delmar ), 1857-1948
Place of Publication:
Washington, D.C.
Publisher:
U.S. G.P.O.
Publication Date:
Language:
English

Subjects

Genre:
federal government publication ( marcgt )
serial ( sobekcm )

Record Information

Source Institution:
University of Florida
Rights Management:
This item is a work of the U.S. federal government and not subject to copyright pursuant to 17 U.S.C. §105.
Resource Identifier:
029626242 ( ALEPH )
03918976 ( OCLC )

Downloads

This item has the following downloads:

contributionstow00hopk_0_0043.txt

contributionstow00hopk_0_0008.txt

contributionstow00hopk_0_0031.txt

contributionstow00hopk_0_0039.txt

contributionstow00hopk_0_0021.txt

contributionstow00hopk_0_0067.txt

contributionstow00hopk_0_0085.txt

contributionstow00hopk_0_0069.txt

contributionstow00hopk_0_0062.txt

contributionstow00hopk_0_0045.txt

contributionstow00hopk_0_0075.txt

contributionstow00hopk_0_0033.txt

contributionstow00hopk_0_0076.txt

contributionstow00hopk_0_0012.txt

ER0TJEHCG_G3QY64_xml.txt

contributionstow00hopk_0_0027.txt

contributionstow00hopk_0_0005.txt

contributionstow00hopk_0_0058.txt

contributionstow00hopk_0_0073.txt

contributionstow00hopk_0_0042.txt

contributionstow00hopk_0_0040.txt

contributionstow00hopk_0_0065.txt

contributionstow00hopk_0_0014.txt

contributionstow00hopk_0_0053.txt

contributionstow00hopk_0_0013.txt

contributionstow00hopk_0_0035.txt

contributionstow00hopk_0_0068.txt

contributionstow00hopk_0_0023.txt

contributionstow00hopk_0_0020.txt

contributionstow00hopk_0_0082.txt

contributionstow00hopk_0_0064.txt

contributionstow00hopk_0_0049.txt

contributionstow00hopk_0_0055.txt

contributionstow00hopk_0_0083.txt

contributionstow00hopk_0_0063.txt

contributionstow00hopk_0_0052.txt

contributionstow00hopk_0_0029.txt

contributionstow00hopk_0_0071.txt

contributionstow00hopk_0_0041.txt

contributionstow00hopk_0_0074.txt

contributionstow00hopk_0_0089.txt

contributionstow00hopk_0_0086.txt

contributionstow00hopk_0_0010.txt

contributionstow00hopk_0_0011.txt

contributionstow00hopk_0_0081.txt

contributionstow00hopk_0_0038.txt

contributionstow00hopk_0_0016.txt

contributionstow00hopk_0_0028.txt

contributionstow00hopk_0_0017.txt

contributionstow00hopk_0_0061.txt

contributionstow00hopk_0_0050.txt

contributionstow00hopk_0_0054.txt

contributionstow00hopk_0_0070.txt

contributionstow00hopk_0_0051.txt

contributionstow00hopk_0_0026.txt

contributionstow00hopk_0_0048.txt

contributionstow00hopk_0_0019.txt

contributionstow00hopk_0_0018.txt

contributionstow00hopk_0_0034.txt

contributionstow00hopk_0_0015.txt

contributionstow00hopk_0_0060.txt

contributionstow00hopk_0_0090.txt

contributionstow00hopk_0_0022.txt

contributionstow00hopk_0_0037.txt

contributionstow00hopk_0_0056.txt

contributionstow00hopk_0_0084.txt

contributionstow00hopk_0_0093.txt

contributionstow00hopk_0_0072.txt

contributionstow00hopk_0_0024.txt

contributionstow00hopk_0_0047.txt

contributionstow00hopk_0_0088.txt

contributionstow00hopk_0_0094.txt

contributionstow00hopk_0_0046.txt

contributionstow00hopk_0_0078.txt

contributionstow00hopk_0_0007.txt

contributionstow00hopk_0_0002.txt

contributionstow00hopk_0_0001.txt

contributionstow00hopk_0_0059.txt

contributionstow00hopk_0_0087.txt

contributionstow00hopk_0_0009.txt

contributionstow00hopk_0_0066.txt

contributionstow00hopk_0_0025.txt

contributionstow00hopk_0_0006.txt

contributionstow00hopk_0_0077.txt

contributionstow00hopk_0_0044.txt

contributionstow00hopk_0_0057.txt

contributionstow00hopk_0_0079.txt

contributionstow00hopk_0_0036.txt

contributionstow00hopk_0_0080.txt


Full Text



U. EPRTMEN OQF AGRICULTURE,

L. 0. HOWARD, Entomologist and Chief of Bureau.

CONTIBUIONS TOWARD A MONOGRAPH OF
ATHE SCOI1YTID BEETLES,


11.-PRE IINARY CLASSIFICATION OF THlE,

SUPBRFAILY SCOLYTOIDEA.


BY

A.D. HOPKINS, PH. D.,
In Cargeof For'est Insect Irnvestigations.




4 ~ ISSUED JANUARY 9, 1915.4






WkTM








S9 GVERNENTPRINTIN~G OJTIOR.









TECHNICAL SERIES, No. 17, PART II.

U. S. DEPARTMENT OF AGRICULTURE,
BIUREA.U OF IN'I> M()L( )GY.

L. O. HOWARD, Entomologist and Chief of Bureau.


CONTRIBUTIONS TOWARD) A MONOGRAPHI OF
THE SCOLYTID BEETLES.





II. PRELIMINARY CLASSIFICATION OF THE

SUPERFAMILY SCOLYTOIDEA.




BY


A. D. HOPKINS, PH. D.,
In Charge of Forest Insect Investigations.






ISSUED JANUARY 9, 1915.





















WA SHING TON:
GOVERNMENT PRINTING OFFICE.
1915.




















B UREA U OF F-VTO MOLOG Y

L. 0. How.kizr), Eilfolool(wl',4 (11),7 C. L 'MARLATT, OW/
R. Chic)'(7crl: olid

F. 11. CITITTENDEN, i ? rhor of toick crop olld, Iol- (l prodlict
A. 1). 1l()PKT-,,1; ir c 'osrct iorrshpitiMis.
AV. 1). 1-1 UNTER1 i ] c/m/.qr o/' (ro fif 1(/ t osic! iore,,;C F. M. o ch(iqle 0'(iroll
A. L. QIUAPI TANCF. i1i C/ol,'(P 01,(hc1*(h1o,1, j

A. F.
ROLLA 1'. io o1'('(i,'1or1*, 7
MABEL ('()I.( ORD, /in A u / (;' ()/' iI)r';!.y.

Fo i) i-: 'r INSECT INVESTIGAMONS.

A 1). HOPKINS, iit

If. E. BURKE, AUGUST f))-U,,SCK, W. D. JM F-14' PTZT-NNF j,. T. F.'- NYDERI
F. C. CRAP-1HEAD, J. M'. All!,LER, S. A. lllomvi, iz, A, C, C. T. (;izii- \r
W. S. JACOB KOTPsi -i-, B.T. 11AUVE), 00100701(liC111
CAPI, 11EI\NP 11. A. B. ('11A)II'LAIN-, WAL AIIDOLFTON, MANY 1". FAL IAIZY
J tj, ist(tnts.
61 o. BOVER1
WA(;N1-,1',, W. E. 6LENDINNIN.J.', J. (1. EVENDEN 1". 11. lirul;vl-r. 1'. 1,
Jl It. 1,01.1.ocK, 1?towoioyicul E ]"ACAN. FuzAm:,ru ATA-Ul)i;, TAYLOR, 'EDN-A ITASLI-P, P! .VRL
L. BOONE, pnlwio"Ior, .. .......... ...
altesignedApril 1, 1914.















C() N E N T S.

1'age.
I n tro d u c tio n - - - - .- .-- - . I G 5
Position of the Scolyvoidea -----------------. .. .. ..---------------------- 167
G general anaomy ..................................... ............... 168
T axoonooy -----------------------------------------------. 169
M orph ological ch aracters ................................. ............ 169
Superfamily charaW I us ......... . .. 169
Family charater ;- ------------------- ----------------------170
SFamily character -------------------------- --------------- 17 0
Subfam ily character, ................... .......................... 170
Generic characters-- ........--------------------------....... 1I
The antenna -------------------------------------------------- 171
The eyes ..................................................... 174
The mouthparts -----------.--------------------------------- 174
Characters in general- .------------------------------------ 175
The body ----------------------------------- -. ------------ 175
Form ------------------------------ ---- -------- 175
Color -------------------------------------------------- 176
Vestiture ---------------------------------------- 176
Sculpture --------------------------------- ------- 176
Armature ------.--------------------------------------- 176
Head------------------------------.-------------- 177
Prothorax --------------..---------------------------------1 77
M esothorax -----------..................... -.............. 177
Metathorax---.--------.------ -------------------- 178
Legs ------------------------------------------------------ 179
Elytra ---------------------------------- --------------- 179
P osterior w ings --------------------------------- 179
A bdom inal termites .................................. ...... 1 0
Abdominal spiracles -------------------------------------- 181
Abdominal sternites -------------------------------------1 82
Stridulating accessories- -------............................ 182
Internal anatomy -------------------------------------------- 183
Digestive system -------------------- -------- 183
Proventriculus ---------------------------------- 183
Reproductive organs --------------------------------------- 184
The reproductive organs of the male ---------------- -... 184
Posterior elements ................................. 185
Anterior and median elements ...................... 190
Variations and combinations of the elements -------- 190 Terminology of the reproductive organs ---------------- 192
Classifications based on the reproductive organs ......... 194
Secondary sexual characters .................................... 195
The pupa ....................................................... 196
The larva ....................................................... 197
The eggs ......................................................... 197
The embryo ------------------------------------------------------ 197
III






IV CONTENTS.

Taxonomy-Continued. Page.
Physiological characteristics ............................................. 198
General habits ---------------------------------------------------- 198
Classification according to habits ................................... 198
Food habits of the adults -------------------------------------- 199
Food habits of the larve ------------------------------------- 199
Pupal habits --------------------- -----------------------199
Flight habits ------------------------------------------------ 200
Social habit-------------------------------------------------- 200
Galleries ----------------------------------------------------- 201
Terminology of the galleries --------------------------------------- 202
Classification of the galleries ------------------------------------- 204
E gg galleries --------------------------------------------204
Larval mines ------------------------------------------------ 204
Types and subtypes of egg galleries --------------------------- 205
Relation of types of galleries to the subfamilies aynd families. 206
Taxonomic relation between the beetles and their host plants ........ 207
Part of plant selected by the beetles---------------------. 207
Co d to ofte"l n ....... ......... ..... ................... 0
Condition of the plant--------------------208
Relation of the species of beetles to the systematic position of
their host -------------------------------------------------- 208
Range of host plants .......................................... 208
Associations of species of beetles and species of plants ............ 209
Summary of taxonomic evidence furnished by host relations .. 209
Geographical distribution in its bearing on taxonomy ------------------- 210
Review of taxonomic characters and characteristics ...................... -211
Morphological characters ............................................ 212
Physiological characteristics ...................................... 213
C orrelation of morphological and physiological elements------ ------213
Parallel modifications ---------------------------------------------- 214
R eversals ......................................................... 214
Progressive m odifications .......................................... 215
Examples of progressive modification ........................... 215
Statistical taxonomy --------------------------------------- ----------- 216
The species --------------------------------------------------------------- 216
Varieties, races, etc ....................................................... 216
The genus --------------------------------------------------------------- 217
Nomenclature ------------------------------------------------------------ 218
Types of genera......................................................... 219
Genus Scolytus Geoffroy. ............................................ 219
G enus I ps I)e G eer .................................................. 220
Gemis l'omicus Latreille .............................................. 220
(jenus I1 vlastes Erichson ...............-............................. 221
Genus Ciryphalus Erichson ............................................ 221
Genus II po \Ves wood-- ......2................................. 221
(enus I x'gral lus- ......................................... 222
(senUS K irby ............................................... 222
I)(esript ion of a new geuts and species ..................................... 222
Preliminary classi~iiat ion of the Superfamily S.olytoidea--------------. 224
y o, t a ilies --.................................................. 224
I division ....................................................... 224
Su d iv i ion A ............................................... 224
a uly Ipid ............................................ 224





CONTENTS. V

Preliminary classification of the Superfamily Scol( ytoliea-Continued.
Key to the families-Continued.
Division I-Continued. Page.
Subdivision 1 ............................................... 225
Family Scolytida ........................................ 225
Family Scolytoplatypodide ............................... 225
Division II ......... 2 ........................................... 225
Subdivision C ................................................ 225
Family Platypodidw ...................................... 225
Family Ipide. Key to the subfamilies ............................... 225)
Division I ...................................................... 225
Subdivision A .............................................. 225
Subfamily Cryphalin ................................. 225
Subfamily Ipin..................................... 225
Subfamily Corthylinv .................................... 225
Subfamily Micracina ..................................... 225
Subfamily Webbing .................................... 225
Subdivision B .............................................. 225
Subfamily Xyloctonina ................................. 225
Division II-.................................................... 225
Subdivision C .............................................. 225
Subfamily Crypturgina .................................. 225
Subfamily Phlotribinc.. ---- *--...................225
Subdivision D ............................................... 225
Subfamily Hylesining .................................. 225
Subfamily Phloeoborina .................................. 225
Family Scolytid.. Key to the subfamilies ........................... 225
Division I ...................................................... 225
Subfamily Coptonotinae. ............................. 225
Division II ...................................................... 225
Subdivision A .............................................. 225
Subfamily Hexacolinoe .................................. 225
Subfamily Bothrosterninx ............................... 225
Subfamily Hyorrhynchin .............................. 225
Subdivision B ............................................... 225
Subfamily Camptocerino ................................ 225
Subfamily Scolytinv ................................... 225
Family Scolytoplatypodide ......................................... 225
Family Platypodid?. Key to the subfamilies ......................... 225
Division I ...................................................... 225
Subfamily Platypodinoe .................................. 225
Division II ...................................................... 225
Subfamily Genyocerina .................................. 225
Subfamily Chapuisina ................................... 225
Position of the principal described genera in the preliminary classification ------ 226 Genera described in 1911-12, not included in foregoing list, but here provisionally assigned to the subfamilies ................................... 227
Genera of doubtful position .............................................. 228
Bibliography ............................................................ 229















I L1,t'sTrR ATrio N s.



PLATES.
Page.
P~LATE IX. Figs. 1-18-Typical tarsi aiid tibia,, of the suibfanhhiecs of Scoly-t oidea--------------------------------------------------- 170
X. Figs-,. I-3a.-Anten ii~ of typical species of the subfainilies of ScolytoidCe --------------------------------------------------- 170
X1. Fig-s. 7-l0a.-Antennte of typical species of the subfamilies of
Scolytoidea---------------------------------------------- 10
XII. Figs. 12-18b.-Antennme of typical species of the subfamilies of
Scolytoidea---------------------------------------------- 170
X II. Figs. 1-9b.-Tibia aiid tarsi of typical species of the subfamilies of
Scolytoidea, ---------------------------------------------- 17'I
XIV. Figs. 1-l0b.-Tibioe anid tarsi of typical species of the subfamillies
of Scolvtoidea, ------------------------------------------- 17 8
XV. Figs. 12-15b.--Tibia- aiid tarsi of typical species of the subf'anilies
of Scolytoidea-------------------------------------------- 178
XVI. Filrs3 16-18b---Tibia- and tarsi of typical species of the subufamilit-s
of Scolytoidea-------------------------------------------- 178

TEXT FIGU-RES.

Fiu;. 9(;. The antenna in scolytoidl leetles: Diag'ram anid terninowlogy......... 172
9 7. Abnoriwalities in the, anenl funicle of Xyleboras tuckygrJApuS -------173
9.IP euuu-qilils: Proventrictilar plate---------------------------- 183
09. Scolylts scd)lilH:o Proventricular plate ---------------------------- 183
I00. Crossotalrsot lcC-ontei: Provenjtricular plate ------------------------ 183
101. Dendroctowlos ralcus:AMemibranotis and nonchitinous elements of niale
repro~uetivcorga --------------------------------------- 184
102. Xyb1 1 borIus s, I S C IIi : Chitinioti elements of male reproductive organs- 184 10:1. Ips ,m //I,(liUwilli: Chitinouis el-rmnents of male reproductive organs.-- 185 104. I'gph rs-)'.: ('hitiniols (,I :11inents o1 male reproductive orga -- 18 186
I (Y5. PityiophihoruIs b) ibis: Enid plate.s4 anid semial rod of male reproductive
4 ransj ------------------------------------------------------18S6
I 06. ifiraI'Ss i/is: 11,sterior elem(,nts o4 male reproductive 0rgn5118.. 86 10 7, 1),'11 oo I s I ( /lII ns (: 4 oseIor eleme1n, )1 IIt s o)f m alIe rep roduIIc t ive org"-1ans1. 187 I WIS. Scolyf a1s r/ 1,JIosus: Pul"t erlor elements; of male reprn~hictive or IliS 19
109.1 AS c-;o/h/ useadijnzss osterior eleineits of male rpoutv
orai------------------- ----------- ----------------------189
I 10. (,rstfrssicn :Ps erirelmnts of maitle reproduictve orgais- 19A
I 1 .I ) Iilruclon us rui ws: Feaere:)roimwti e organs-------------------1941
112. ( Iwiieto f glresof Scoltoidea--------------------------- 205
VI











U. S. D. A., B. E. Tech. Ser. 17, Pt. I. F. I. I., January 9, 1915.

CONTRIBUTIONS TOWARD) A MONOGRAPH OF THE SCOLYTIID BEETLES.


II. PRELIMINARY CLASSIFICATION OF THE SUPERFAMILY
SCOLYTOIDEA.a
By A. D. HOPKINS, Ph. D.,
In Charge of Forest Insect Investigations.
INTRODUCTION.
The object of this contribution is to discusss the taxonomy and present a preliminary classification of the families and subfamilies of the scolytoid beetles of the world. The discussion and classification are based on a study of representatives of about 122 described and undescribed genera and about 1,000 species of North America and other countries, in the collections of the U. S. National Museum and certain other museums and institutions of this country.
The types of North American species described by Zimmermann, LeConte, Fitch, Harris, Schwarz, Ulke, and, with a few exceptions, those of other North American authors, have been studied by the writer. Nearly all of the North American species described by Eichhoff are represented in the U. S. National Museum collections by specimens sent by him to the writer and to Dr. C. V. Riley.
Many of these specimens are from the type series not only of North American but of many foreign species described by Eichhoff. Central and South America, the West Indies, the Eastern Continent, Australia, and Oceania are represented to a greater or less extent by described and undescribed species, of which 31 genera and 96 species are from Europe, principally from the collections of Eichhoff of Germany, Blandford of England, and Villard of France.
The material in the forest insect collections of the Bureau of Entomology and the West Virginia Agricultural Experiment Station, collected by the writer and his associates, includes nearly all of the described North American species and in addition a large a See Hopkins, A. D. List of generic names and their type-species in the coleopterous superfamily Scolytoidea. Proc. U. S. Nat. Mus., vol. 48, No. 2066, pp. 11.5-136,
December 16, 1914.
165





166 THE SCOLYTID BEETLES.

number of undescribed species and a great amount of new biological material. With this amount of material at hand and a special study of this group of insects extending over a period of twenty years, the writer feels justified in proposing a revised classification and in defining the characters which it appears to him are of special taxonomic importance.
In presenting the preliminary classification of the Scolytoidea the author does so with no idea of criticising the systems proposed by other authors. The whole presentation is simply to stand as the writer's interpretation of the characters and characteristics represented by the material before him, and to serve, so far as it may, as a step in the evolution of artificial systems of classification toward the ideal or natural. Each comprehensive system of classification
proposed since that of Linnous has contributed something toward the evolution of better systems. Some of them have been progressive, others in part retrogressive, and a few have been revolutionary in their character. But, as in most conflicts of opinion, general progress results. Therefore those investigators of the present and the future who, without prejudice as to any opinion or theory, can sift out the true from the erroneous in that which has been published, and add new truths from their own observations, will make the most rapid progress toward the attainment of the ideal.
The anatomical investigations conducted by the writer and outlined in Part I of this bulletin have revealed heretofore unrecorded facts relating to structural characters, which, in connection with a greatly increased knowledge of the physiological characteristics of the stages of development and of the habits, host relations, and distribution of described and undescribed forms, seem to warrant a somewhat different classification from those proposed by other writers.
It seems that a study of the facts as revealed by modifications in morphological characters and physiological characteristics of existing forms, without any attempt to explain their origin or phylogeny, will lead to a more correct interpretation of natural affinities than any amount of speculation on hypothetical ancestral forms from which present species may have evolved. Indeed, it would seem that we have, in the progressive modification of the more fundamental and dominant characters and characteristics, a better taxo11011ic basis on which to correlate the characters and construct a so-ca tle I natural system than can be found in those characters which are subject to special modification through similar use and influclices or elvilnnieit *t.a
a1 I this connection ee Part I of this bulletin, p. 25, second paragraph, and pp. 67-68.





PRELIMINARY CLASSIFICATION OF SCOLYTOIDEA. 167

POSITION OF THE SCOLYTOIDEA.
The contrasting characters which indicate the position of the superfamily Scolytoidea in the order Coleoptera are as follows:
Order COLEOPTERA.
Maxilla undivided, the palpi rigid and with not more than three joints; larvfc legless .................................................. Suborder Rhynchophora.
Maxilla divided, more or less flexible, and with a flexible palpus, usually 4-jointed;
larve rarely without legs ............................. All other Coleoptera.
Suborder RHYNCHOPHORA.
Head without prominent rostrum or beak and the submentum never produced into a gular peduncle ...................................... Superfamily Scolytoidea.
Head usually with prominent rostrum or beak and the submentum always more or less
produced into a gular peduncle ........................ All other Rhynchophora.
It is evident to the writer that, in consideration of the extremes in morphological characters to be found in the order Coleoptera, the superfamily Scolytoidea occupies a position opposite to that of the Carabidea, and that in the Rhynchophora it occupies an opposite position to that of the Apionidx.
It seems desirable to place the Scolytoidea first in the classification of the Coleoptera, not because of any theory as to their origin or phylogeny but because their elements of structure seem to form a better and more correct basis from which to proceed in the interpretation of the progressive modification of the characters which serve to distinguish the major and minor divisions and groups. Such a method should not conflict with other methods because it should make little difference whether we begin with the Scolytoidea or the Carabide. If the interpretation of the progressive modifications and natural relations is correct, the relative positions of the various groups will be the same, or similar. It is simply a matter of choosing between the two directly opposite methods to attain the same result and of adopting the one which seems to be more in accord with the natural course of change or evolution from one extreme to the opposite.
If we begin with the *colytoid beetles we find throughout the suborder Rhynchophora two dominant ,or constant characters, namely, the rigid maxillm and the .legless larvm. We find also certain changeable characters repeatedly paralleled in the various major and minor groups, and that the general progressive modification of these characters, as, for example, the tendency toward a prolongation of the head, represents a separate and greatly diverging line of morphological expression or evolution from that prevailing in the other divisions of the Coleoptera.
In the other divisions of the Coleoptera the divided maxilla, with flexible palpi, and the legged larvoe are the prevailing and more domi-





168 THE SCOLYTID BEETLES.

nant characters. Here, again, there are a number of changeable and frequently parallel characters, the progressive modification of which shows many diverging lines toward the extreme, as, for example, the greatest development of jointed and differentiated appendages a in the larve, the large size, the odd shapes, and the extraordinary elements of structure and habit.
It is evident that the scolytoid beetles could not have been derived from the highly differentiated carabids or scarabaids and that these groups could not have been derived from any existing group of the Rhynchophora. It is also evident that the species in the two primary divisions of the Coleoptera which may be the nearest representatives of their primitive ancestors are themselves so highly differentiated from one another and from ancestral forms of Coleoptera that they can not be recognized, or, if they could, they would be of little or no use as a basis for speculation on the origin and evolution of the order; then, too, we have no material in fossils on which to base a reliable hypothesis, because only the highly specialized forms have been preserved. Therefore we must rely on facts as they exist and endeavor to discover and interpret the elements of distinction and relationship which have survived in the course of their evolution, under the influence of natural selection, dominant differentiation, and progressive and parallel evolution. The writer's interpretation of these facts, so far as they apply to morphological characters and the distinction of groups and species, will be expressed in the tables of families, subfamilies, genera, and species, in the succeeding contributions toward a monograph. as will also the progressive modification of characters indicative of the lines of divergence from one extreme toward the opposite.
GENERAL ANATOMY.

The discussion, illustrations, and terminology of the anatomical elements of Dendroctonus given in Part I of this bulletin will serve as a basis for comparing the anatomy of representatives of other genera. The writer has made a detailed study of the entiiroe anatomy
(of only a few representatives of other genera, but the more important el(ilnts o()f thw external and internal anatomyi of representatives of all of t hI(e genera in the local collections have been studied, involving thle preparation of over 1,200 microscope slides. This, together with tihe work o()f other investigators, notably Lindemann, Niisslin, Fuchs, and Eichhoff, gives us a basis for a somewhat comprehensive
VIPW O f lic 1U fit( )) 1t', fel~ls 0 O ,811111 110 111lou t
\'J w (4f t} c su(ib je('t. 'iere rmalns, howe-er, an immense amount o()f aiatomical work to be done before a knowledge of theI subject is anything,,, like complete.
aTlp i .r 1i 1As 1hat it is ])y ,)means v t L1t harvwe with jointed apjwndas are mn, r, prillt dim th \1s1 wit hout such appendages.
&





PRELIMINARY CLASSIFICATION OF SCOLYT IDEA. 1I W

TAXONOMY.
MORPHOLOGICAL CHARACTERS.

The principal miorphological characters adopted by the writer to distinguish the fanlilies, subfamilies, aul genera, and the major and minor divisions of each are to be found in the external anatomy of the imago. Ilowever, some consideration has been given to the
location of correlated characters i the internal anatomy and in the physiological characteristics of the different stages of development from the egg to the imago.
It has seemed(l to the writer that in order to have a (1aification which would indicate natural positions and lines of nlt1(lification, and at the same timo be simple and practicable, we shouldvor to locate and utilize, as far as possible, external characters which are readily available for examination by a hand lens or the microscope without serious mutilation of the specimens by those who make use of the systematic tables and descriptions. The small size of most of the scolytoid beetles renders it difficult and tedious to examine the minute and obscure elements of the external and internal anatomniv, such as the mnouthparts and the digestive and sexual organs. It is very important, in fact essential, that the taxonomist should study in detail, and comprehensively, the various elements of externd and internal anatomy in order to have a broad basis for his conclusions, but the general student and investigator should not be required to go to such extremes in order properly to interpret the conclusions. Therefore it has been the object of the writer to conform to the simple method of expression rather than to that involving a complexity of detail.
The principal character-bearing parts of the external anatomy which appear to serve as the best taxonomic guides toward a natural system of classification are mentioned in the following pages merely as a basis for the preliminary classification, which is subject to revision in the more detailed treatment of the several subfamilies.
SUPERFAMILY ('HARAC TElS.
The superfamily is at once separated into two primary divisions by the relative length of the first tarsal joint, and the subdivisions, sections, and families are distinguished by characters of the tibia (P1. IX). It is interesting to note that while the most dominant character is found in the first joint of the tarsus, the modification of this joint within the families, subfamilies, and genera is of minor importance. The same, to a lesser degree, may be said of the tibia, in which the character of the apical angles is constant within each subdivision of the superfamily but the modification of these angles





170 THE SCOLYTID BEETLES.

throughout the minor groups to the species, except in a few cases, is of little or no importance.
The complete opposition in the characters of the apical angles of the tibia, as shown in the subdivisions, is of special interest. There is no apparent explanation on any theory of use or natural selection, but it does appear to signify widely diverging lines of descent in which this reversed element in the two subdivisions has remained as the dominant and distinctive character.
FAMILY CHARACTERS.
In the classification of the families Ipidae and Scolytidae into subfamilies the principal characters used to distinguish the divisions are found in the head (2)a, pronotum (4), and tarsi (2).
The subdivisional characters are found in the antenna (2), tibia (2), and abdominal sternites (2).
The sectional characters are found in the antenna (2), eyes (2). pronotum (2), tibia (4), and form of body (2).
The subfamily characters are found in the pronotum (4), antenn
(2), seventh abdominal sternite (2), elytra (2), and third tarsal joint (2).
It will be seen that in the classification of the two families into subfamilies the principal characters are found in the head (8), pronotum (10), and tibia (7).
SUBFAMILY CHARACTERS.
In the classification (in manuscript) of the 16 subfamilies of Ipidae and Scolytidae into genera the principal character-bearing parts for the divisions, subdivisions, and sections are as follows:
Divisions: Head (1), antennal club (3), funicle (3), eyes (4), epistoma (2), maxilla (1)-total for head (14); pronotum (5), tarsi (3),
and elytra (2).
Subdivisions: Antennal club (5), eyes (4), funicle (2), epistoma (1), maxilla (1)-total for head (13); third tarsal joint (2), anterior coxai (3), seventh abdominal sternite (2), and pygidium (2).
Sections: Antennal club (4), funicle (2), eyes (1)-total (7).
It will be seen that in the classification of the subfamilies the character are found in the head (35), tarsi (7), pronotum (5),
clytra (4), coxam (3), seventh abdominal sternite (3), pygidium (2), and tibia (1).
Su bsections and series to genera: The (lichotomous characters of the su)sec(tions alnd series and the distinctive characters of the genera are as follows: A nteiial club (13s), funicle (110), scape (7)-total for a The numilwr following the nameof a structure indicates the relative importance or the uitber of tines it figures in the (dichotomy.







Tech, Series 17. Part 11, Bureau of Enton,c) ogy, U. S. Dept. of PLATE IX.










1 2 3 4 5 7 8 9 10 12 13 1 16











2 4
>

55







6 7 8 9 10











12 13 15 16



















.7



is

TYPICAL TARSI AND TIBI.* OF THE SUBFAMILIES OF SCOLYTOIDEA.
Fig. 1.-Cryphalina- ( Cryphalus asperatus). Fiz. 2.-lpiw-e (1/). ? typographus). Fig. 3--Corthvlin t
(Corth lus columbianus). Fig. 4.-Alicracinm -1ficracis suturalis). Fig. 5.-Webbiwe ( IVebbia' diptcrocirpi). Fig. 6.-Nyloetonin -e (Xyloctonus scolytoidee) (adapted from Lichhoff). Fig. 7Crvpiiirginm(Cryptui-gu. pv., illus). Fig. 8.-Phla-otribinm (Phlaotribu. olew). Fi-.9.-Hvle.,;inin,:v
(1 ?jlesinn,5crenatus). Fig. lo.-Phleeoboriii e(Phtrfoborii. rit(lis). Fig. 12.-Hexae-o1ime(Hexacob/,
sp.). Fi,,. 13.-BothroiterninT (Bothro-sternus sculpNzy-Wus). Fig. 15 -CarnptocerinT ( Ca
toceruT.,,neipennis). Fig. 16.-Scolytinja (Scolytusscoiijl ls)_ Fig. 17.-Seolytoplatypodinm (Scolltoplatypussp.). Fig. 18.-I-Ilatypodinoe (Platypus cylinders). (Original.)







Tech. Series 17, Part 11, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE X.
















(Z'





V/





Jb
3a

'y 60





















60









7'






y 4160
ANTENN,,E OF TYPICAL SPECIES OF THE SUBFAMILIES OF SCOLYTOIDEA.
Fig. 1. e I 11phatil": (Isp(r(ttil Y Wr vp1mlimo), nweriora,;pecl of left antenim. Fiz. 1(r.- Po- tvrior aspect I'ig.2. Ips iypoqvi ph us (I pim v),aiit crioras pect of left 11111 (111 W1. Powrior tlwct of Ivft antenna of sane. Fig. 3. Coithyliv; (Cor1hylilm'), felmile,
:mlvrior :i pvcl of left anicnim. Fh 3a. --Fetwile of same, Ix),"Ivrior aq)ect of left alitelma. Fiv. : b M:Ilc of (.11111. Fiv. 'I.-- Ifi(vtcis silturalis female, aw erior a,;pect of left,
:1101'111M. Viv- Ia. Vemide of same, posterioraspeo of left, antemia. Fig. lb.-Male ofsame, scape.
'-f --). lVebbia dipf(rouarpi (N\ vhhinx), anterior a, pvct of left antenna. Fig. 5a.-Posteriur aspect of lert ;kilwillm of ':k1111" wri"'ill:IL)







Tech. Series 17, Part II, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE Xl.


70


I 8I



































)(60X/0
//
1,'












































ANTENNA" OF TYPICAL SPECIES OF THE SUBFAMILIES OF SCOLYTOIDEA.
Fig. 7.- Crypturgus posillus (Crypturgina), anterior aspect of left antenna. Fig. 7a.-Posterior aspect of left antenna of same. Fig. 8.-Phlcotribus olex (PhbcotribinT.), anterior aspect of left antenna. Fig. ba.Posterior aspect of left antenna of same. Fig. 9.-Hylesinus crenatus (Hylesimumn~), anterior aspect of left antenna. Fig. 9a.-Posterior aspect of left antenna of same. Fig. 10.-Phlceoborus rudis (Phbcoborinmi) anteor aspect ofieft annn a Fi 1a Poserior aspect of left antenna of same. (Oniginal.) ~ ~/
y O
)
#i/,S," ,/>



., ,X.,z >s+ /











,i it

















ANTENNAE OF TYPICAL SPECIES OF THE SUBFAMILIES OF SCOLVTOIDEA.
Fig. 7.- Crypturgus puillus (Crypturgin~), anterior aspect of left antenna. Fig. 7a.---Posterior aspect of left antenna of same. :Fig. 8 .-Phlo~otribus olea (Phlaeotriina'), anterior aspect o f left antenna. Fig. 8a.Posterior aspect of left antenna of same. Fig. 9.-Hylesinus crenatus (Hylesinin~e), anterior aspect of left antenna. Fig. 9a.-Posterior aspect of left antenna of same. Fig. lO.-Phleoborus rudis (Phlzoborina2), anterior aspect of left antenna. Fig. l0a.--Posterior aspect of left antenna of same. (Original.)






Tech. Series 17 Part 11, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE X11.





2a Ile




12










X60





A














.... ......


..........







17a














6

17

hy




ANTENNA OF TYPICAL GENERA OF THE SUBFAMILIES OF SCOLYTOIDEA.
J-i-,. 12. 11,jacohis ,p. (Ilevicolirw,), :miciior :ipvct. (or left :mlviin i. 12a 1'()-l vrior lspvcl of left
o r -;lyllv' V ig ( lk )tll1o 1c1-1J 1l;f' :i1l1eTii)1-w 'jov('1 o flefl .111tetill"I.
h)-101-jol' ',1 1)0-1 41f Ivfl :mlcllii l()f 'mllv. l'iv. ].-). t (linjoloc(rils ('?ve 11)(11111s ;I pvct (if 101 allivilila (if felwilv. I, iv. I.-W. ('11111 of fv111:11v Scapv of 111,11f, of
Ill:[, :1111vi lot, 1'-;pvcl of leff onlenim. Fii, ]I'll.- Po, Ivrior
I tio-cl (if 1441 :1111clill:1 of -:Mlv 17., Scdilloplaollms ,p. vit)phl v po, I inn, I niflviior iiq)ect of
14. f I :[ 1] 14 .1111: 1. 1 i,-,. I 7a. P o'l 411 i(ol' ;1, 1 It-Ut o f 1(4 1 Ililt ('11111L o f S:11110. I i '-'. I '. I'M / 1/ 1, 1j'N C o// i 11 dil. it S ( P hilt yill.4, i, ;lilt (-I tilt :t li('(.l lot lifl ;lilt of female. FiL Lsa.-Posterjor -ispect. of 1(ift nriteiiiia ol sanie.






PRELIMINARY CLASSIFICATION OF SCOLYTOIDEA. 171

antenna (145); eyes (143), epistoma (6), front of head(l (2)--total for head including antenna (297); pronotum (29), elytra (12), tarsi
(8), tibia (6), form of body (5), pygidium (2), abdominal sternites (2), and coxe (5). Thus it is shown that the most important generic characters are found in the antenna and eyes.
A summary of the principal character-bearing parts, as recognized by the writer in his preliminary classification, may be tabulated as follows:
TABLE I.-Summary of principal character-bearing parts in the sopetrf(i ilU Scolytoidra.

In the subIn the su- In the In the sub- sections
Characters. perfamily. families. families, and < ries
to the
genera.
Times used. Times used. Times used. Times used.
Tarsi, first joint ................................. .. 2 ............ 7
Tibia, apical angles .................................... 3 ------------........... 1 6
Head.............. 8 35 297
ea-- ---------------- ---------------------------- ----------- 8 29
Pronotum .....................--------------------------.... .. ....... ............ 10 5 29
Elytra ................................................ ----------- 2 4 12
Third tarsal joint .........................---------------------------------. ..---.......... 4 7 8
C ox e-...........................- .............. .-... ....... ... .. 3 5
Cox------------------------ ------- -- -- -Seventh abdominal sternite .... ........... .. ------------.......... 2 3 2
Pygidium ............................ .. 2 ...........

GENERIC CHARACTERS.
THE ANTENNAE.
(Fig. 96; Pls. X-XII.)

ANTENNAL FUNICLE.

The antennal funicle is perhaps the most important taxonomic element of the scolytoid beetles. It is one of the first things to be
-ked for as a guide to the combination of characters which distinguish the genus and, at the same time, indicate its position in the .- ssification. While the same number of joints may be paralleled many times in the genera of the same subfamily and in different subfamilies, the writer holds that, with very few exceptions, there must be the same number of joints in the funicle of all of the species of a genus. The exceptions are found in Hypothenemus and Stephanoderes, in which the males are smaller than the females and the antennal funicle has a less number of joints. The males in Xyleborus and allied genera are also smaller than the females, but usually have the same number of joints. Occasionally there is a smaller number or other abnormal developments. (See fig. 97.)
The writer's conclusions are based on the study of balsam mounts of representatives of all of the genera which have been available to him, and of a large percentage of the commoner species. It has been found that a normal variation in the number of joints in the






172 THE SCOLYTID BEETLES.

Z11110 sex Of the species of a well-defined geatis is exceedijigly 1UIV. 'Flierefore aii odd number of joints in examples of the doniiii"-thqr
__ (Ix either indicates zii, almormal development or a different genus.
If abnormalities (wctzry fliey may be easily detected by the combinati(Ql Of other Ji.aracters. The number of joints in the antennal f unicle of the sc( 1.:,.-toid beetles is limited to seven, and tbere is
probably no nominal
exception to this ill t1le supel '11ily, n(I
probalAy not ill tile
F T entil-C P"livilchophora,
or, if Sol it Nvill be exceedill(
V AccoL-dino, to Cie
number of joints i.i f lie funicle flie 221 (renera inclildillo. IIUMV now onesi WT dist, lited ,is follo,)ws:
J
TABLE 11.-F It It i C 71 7 a r
J
L Ncolll O d((I.
I joil)l Ill:), FOPre-w l 1i il)",



rel- ('111111'r -1 -11) 1':1 In 111(".
jolnl.- ill -v!wra repIli 0 11 (1 l"I 1'(1 poI.-Thf, 111!t wrt ill ,col% Joi(I
(1, 1 w-l. Sca /)I.. t', C()nd v, im ()r iwc! d. rlho,. 6 p)IIIIs in 21 "ellerzi repllif"11.111 -1'('l lo ll. i :Ip W id It
Ill P //O/Ch: h, W C(Ol1f1\l(,: 1),1 11 DW
S('( 1:1011. /,'1, :116C,11 ZIIIA (': 0 ). lolw : 17 I] I I ;:I of o; I I 1.-,, 11), do! ,Il ;,1I'_'h'S, oc,', flinicilh i or I -eliera 1,
I oI I I I )1-i l 1, ': 1) 1 I I I(-:I I joint Vub: o, I Tlllll 1:11 iw l.. :I I)i(.:Il re e l) t I I I- Ilj )fzl In d ios.
()I W 11i'd ;1111111h l i'm o f J''illl 1. (1, N -I I I I-(I I t I I I I I o r si I I)( t I I I I; or d'o'hio f I
I Total, "I "vilera repre('1111)hf-lit lit 1-1 w 1, ( 4.o ll 1111111:11 io ll o r "Ill 111%11 ;"111111 [:,1 ioll I 4e li 1 ill- I (; sIll 4 a ll) 11 i(,.,.
fll, 0 1 0 f)14(' W 't ll il I \ (I :111d s''I :11 h"< w u, i\ o 11v [:
c I 11 1141:1. A P ;11i11tl1;11(-d c colic 11. 1)
11 ;ill J, 1 11 1 : F I hicki-nod zil In (,)
G, olili(li 10-1 11 11 )f (4) 11 bt k I I Im sit h ) I I
ho
the ]111 111bel. f J() I I I t S
in flic, flinicle Is 114 (riN-ett in the (Iesci-iptiwi ()f otie (rcuus. Tfiree
IrOll(It',1, litave 5 0110 ha,; G lltl(l three 11,ave joints.
Ir)_1 I
Withill 010 tlW IM-Wrl-OSSIVO 1110(lification in gelielic
4,11,1'raclers wid chal-acterl"tiCS 1,J)JW,11 to 1W 'LS-,0C1,0,C(1 Witli t11V

I'llde Ilwhid('s (bsclIbed -cnera which fi.tvv 1wen provi-





PRELIMINARY CLASSIFICATION OF SCOLYT(II)EA. 173

increase ill thile lnlml)(er of joints in thile funicle. Tl(' excepI)t il to this rule appears to be shown in the Corthyin, where the one-jointed and two-jointed funicles are characteristic of genera whic h, in certain lines, have progressed further than genera in other subtfanilies with five, six, and seven joints. But it is by no) means certainii that these Corthylinm are not highly specialized survivors of one of Ihe mo()st ancient groups in which a one-joilted funicle became the fixe(d and dominant character.
It is interesting to note in Table II that the five-jointed funicle is common to the greater number of genera. All but two of the classified genera with a five-jointed funicle fall in the subfamilies of the Ipide and the
large majority of
them in the first division: while the
genera with a seven- /
jointed funicle fall
in the last part of
Division II of the h
IpideT and in the
family Scolytide.

ANTENNAL CLUB.
The antennal club
comes next to the
funicle as a bearer
of important generic d
characters. T h e FIG. 97.-Abnormalities in the antennal funicle of Xyleborus tachyrange in modifica- graphs: a, Amnterior aspect of right antenna of female; b, posterior
aspect of club of a: c, anterior aspect of left antenna of male; d, pos"S of for l is terior aspect of club and funicle of c; e, anterior aspect of right ciub
tions of form is and funicle of same speimen us c:/, posterior aspet of <: q, posterior from a narrow aspect of right antenna of another specimen; h, anterior aspect of
I g. (Original.)
somewhat c o m
pressed and distinctly annulated club like that of Hypoth/enemus and Pityophtlhorus to the broad, thinly compressed, thickened at base, obliquely truncated, solid conical, or separated joint form.
In 179 genera 123 have a more or less compressed and annulated club, in 44 the club is thickened at base, and in 12 it is conical. In 170 genera 144 are annulated, 36 not annulated, and in 9 the joints are separated. In 136 genera 52 have sutural septa, 74 are without sutural septa, and 10 have chitinized sutures.
It appears that the chitinized septum of the club, while variable and paralleled in different genera, is a good generic character. The sept vary in number from one to four and usually occur toward the ventral margin, but may also occur toward the dorsal margin of one or two sutures. The range of modification appears to be
590260-15-----2





174 THE SCOLYTID BEETLES.

from a club with one or more septa to an annulated club with chitinized sutures and without septa, to a solid club without annulations or septa, or to a conical club with chitinized joints.
The septum is evidently the remnant of the chitinized elements of a movable joint, indicating that the progressive modification of the antemli toward the opposite extreme has been by the process of reduction or fusion of two or more joints, while the modification of thie funicle has evidently been along the line of accession by division as is indicated in the funicle of the retrograde sexual forms (fig. 97) and in the nymphs of certain Hemiptera and Isoptera.
Thus we have in a single organ evidence of progressive modification by reversed processes which is not unreasonable and does not necessarily conflict with the facts and principles of other evolutionary processes.
ANTENNAL SCAPE.

The antennal scape is variously modified from simple and slender to short, stout, dilated, and fringed, but is of less importance as the bearer of generic characters than either the funicle or the club.

THE EYES.

The eyes are variously modified and range from simple, elliptical, round or oval, to emarginate or completely divided and from widely separated on the dorsal or ventral area to approximate on one or on both areas. In 114 genera the eyes in 65 are simple, in 98 emarginate, and in 10 divided. Among those with simple eyes, 4 have them approximate on the dorsal or ventral areas.
THE MOUTHIPARTS.

The characters of the mouthparts have been quite extensively used by systemniatists in the definition of genera, but while the writer recognizes that some excellent characters are to be found in the mouthparts, he is convinced that the are by no means essential for the definition or classification of the genera. The principal objection to their use, as every systematist has doubtless recognized, is that they are not available for interpretation without mutilating the specimin, which in the case of rare or unique specimens and those fromnl other collections is iout of the question. Another serious objection is in the fact that no two balsam mounts of a nmaxilla of the same species present the same contours and angles, and, therefore, these may appear to be quite different except, perhaps, in the number and relative lengths of the joints of the palpus.





PRELIMINARY CLASSIFICATION OF SCOLYTOIDEA, 175

EPISTOI A.

The epistoma in all of the species examineId shows mor' or less important generic and specific characters. Thece is a wide range of modification, from a simple, transverse, chitinous piece within few or no epistomal bristles to the epistomal process of Dendrocto, ts and the exceedingly long epistomal horn of Cactopin us, or the flattned labral-like form in P!icnarthrum.
IIYPOSTOMA.

The hypostoma is also quite' variable and can be used to good advantage in the more detailed definition of a genus or larger group.
LABRUM.

The absence of a true labrum in the adult scolytoid beetle appears to be universal. It has been stated by Eichhoff that it was present in Pycnarthrum, but an examination of a balsam mount has convinced the writer that this is only a produced median area of the epistoma.

CHARACTERS IN GENERAL.
THE BODY.

The size, form, color, vestiture, sculpture, and armature of the body represent characters of more or less importance in indicating lines of progressive modification and as aids in generic and specific definition. The size ranges from 0.4 or 0.5 mm. in the males of some Hypothenemus to 13 mm. in Phloeoborus. While there is more or less variation in the size of the individuals of a species, the length is important not only as a guide to the recognition of a species but as an index to its proper position in the minor section of the genus to which it belongs. The writer has found that, as a rule, the smaller species of a division, subdivision, or section of a genus will, according to other correlated characters, occupy a position opposite to that of the larger species. In the system adopted by the writer the genera with the average smaller species come first in the subfanmily and in each primary and minor division, and in the genus the smaller forms, as a rule, precede the larger. There are, of course, exceptions to this rule, especially in genera with few and widely separated species.
FORM.

The form of the body ranges from elongate and slender to short and stout, and it would appear that the range in progressive modification is from the slender to the stouter forms.





176 THE SCOLYTID BEETLES.
COLOR.
The color, except in a few genera, is of little taxonomic importance. It ranges from pale yellow through yellowish red, reddish brown brown, and black. In a few genera the chitinous integument of the elytra or other parts of the body is bicolored; in others the variegated color is confined to the vestiture. Metallic and iridescent colors are rare.
VESTITURE.

The vestiture is of considerable taxonomic importance. It consists of scales, stout hairs, barbed hairs, plain hairs, fine pubescence, gummy exudations, or adherents. The range in progressive modification of the vestiture appears to be from scales to stout hairs, from barbed hairs to simple hairs, and from a sparsely pubescent to an entirely glabrous body.
SCULPTURE.

In the sculpture of the body there is endless variety. It may be rugose or smooth, the rugosity fine or coarse, the punctures sparse or dense, arranged in rows or confused, regular or irregular in size, irregularly distributed on given areas, etc. Some of the elements of sculpture, such as the rugose or smooth pronotum, are of value in separating the major and minor groups of the families, but the characters of the rugosities and punctures are of special value in defining the smaller groups and species. Concavities and convexities of the front of the head and of the apical declivity of the elytra are often important generic, specific, and secondary sexual characters.

ARMATURES.
The armatures of the pronotum, head, and elytra are important in the definition of genera, speclcs, and sexes. The armature of the head( reaches its extreme development in the epistomal horn of (actopiiiu. Thlie armature of the declivity is strongly developed in X!lb/oru s, X yloclepts, and Eccoptopt rus of the Cryphalinam; in Pitiontf11s a(d lps of the Ipina'; in Hylocurus in the Micracinw; in Anarlhr l't, and Am lhicrnuas of the Corthylinam, and in most of the genera of the Platypodinw. As a rule the modification from a silm>le unaI'rfmed( body to onie with moderately or strongly armed parts is co()rrelated with other (lenments of progressive modification. Tihe Srrnte ariiture of the anterior margin of the p)rollotunm is of (0111i(Icrae) t lxolnomlllic imlprtaiice. The aipical serrations are comIllll iI) ilm ('ryfl )lil111m1 aid I1pim, b)ut rare or absent in the other s11)14.11il T. 1( iextre llcs i ) apical larmatuOre are fou1011( ill ypo/tcutm ,in a i eeIs .1ec., anld in some other species, as, for example, the






PRELIMINARY CLASSIFICATION OF SCol.YT(oIDEA. 177

males of certain species of Xleborus, and in Ain ph icraui fs e atis Blndfd. Tile modiicaltiOi of the apex appears to progress from an apically serrate to a simple one or to one with an apical process.
II EAD.
The head is the most important part of the body in representing the greatest numbnler of taxonomic characters. Its modification is from a short and narrow or broad and globular form concealed from above by the pronotum, toward a narrow elongate form exposed beyond the apical margin of the pronotum. The tendlenecy toward the prolonged subrostrate form indicates a line of progressive modification which is characteristic of the major and minor groups of all of the Rhynchophora, the extremes of which are found in the small, short, globular head of the Ipide and the exceedingly prolonged beak of Apion, Balaninus, and other genera. In the Scolytoidea, Cosmoderes to Stephanoderes of the Cryphaline have the shortest, simplest head, while the extreme is reached in certain genera of the Hylesinine, Hexacolinu, and Chapuisins, with the extreme, or nearest approach to CurculionidT, in Hyluirgops and Hylastes. With a few exceptions the concealed head is characteristic of the first division of the Ipide and the Scolyti&e, while the exposed head is characteristic of the second division of the Ipide and the Platypodidm. The antenna, eyes, and mouthparts have been discussed in preceding pages. The front of the head is of special importance in defining the species and sexes, and ranges from convex and glabrous to deeply concave and densely pubescent.
PROTHORAX.
The prothorax (Part I, figs. 16 and 17, pp. 23-24) represents a wide range of progressive modification from long and narrow to short and broad; the pronotum with sides and base not margined to margined and simple or to emarginate, while the anterior dorsal area ranges from closely and finely rugose to coarsely asperate, and from alutaceous or opaque to smooth and shining. The pleura range from convex to flat and concave, the anterior coxe from contiguous to widely separated, and the sternal, sternellar, and poststernellar areas vary with the form of the prothorax and the size and position of the coxT. The vestiture and sculpture of the anterior median and posterior dorsal and lateral areas often represent generic and specific characters of special importance.
MESOTIHORAX.
The mesothorax (Part I, figs. 18, 19) is exceedingly variable, conforming to the variable form of the body. It doubtless contains many group, generic, and specific characters which may settle difficult






178 THE SCOLYTID BEETLES.

questions of distinction and definition and should be considered in all detailed studies of single genera and allied groups of genera. The scutellum has been extensively used by systematists, and a detailed comparative study of this element in a wide range of genera and species should be made to determine its real significance in taxonomy. The pleurum (Part I, fig. 19) is also exceedingly variable in the form and sculpture of the epimeron, episternum, and preepisternum, while the remarkable structure designated as the preepisternal process (Part I, p1). 29) is of special taxonomic importance since its presence or absence is peculiar not only to groups and divisions of the Scolytoidea but to many other groups of Coleoptera, and evidently represents an extreme in progressive modification which, in connection with other progressively modified elements, will doubtless serve as an index to the systematic position of genera and species. The elements of the sterna (Part I, fig. 18) are also variable, but, like the prosterna, their modification c.-nforms to the variable form of the body, and they are of less importance than the more independent structures like the scutellum and preepisternal process.
MIETATHORAX.
The metathorax (Part I, figs. 20, 21) is quite variable in general characters and especially s:) in some (f the elements of the tergum, probably due to the variable form of the body and the requirements of flight. I'here is considerable variation of this element within the species of a genus and often there are wide differences in allied genera. Perhaps the element subject to the greatest variation is the postscutellum, which ranges from obscure or rudimentary to almost the length of the combined anterior elements. The scutellar groove, the transverse sutures, and the entothoracic ridges or apodemes are also quite variable. The writer has examined the metatergum of quite a large number of species and it would appear that there may 1:e in it some important characters peculiar to minor groups (of genera, but the taxonomic value of the variations is largely limited to the species. It would therefore be difficult to trace correlated lines of progressive modification. Nevertheless, a special compl)arative study of the metathorax shoul Le made o(f a very large number of examples representing all (of the genera to determine whether or not there are special taxOiiOImic elements ()r recognizable lines o()f modification. The episternilum (P)art I, Jig. 20) is quite variable in length, width, sculpture, all(d vet it ure all( is of comsidlerable taxonomic illiportance. The 1eta8t eiia ire ids) valia l l le i co)nflorInity with the varlableO formin of the ImdIY. IiTei stermllim always CCUl)ies the greater part or nearly all (of the area. '1he greatest rage (of variation between the elements of the mtetathorax is to be found in the short and broad forms of the st)uter species (of the 1pidlaw and Scolytida and the exceedingly long ald llarro~v for ,s wculiar to the Platvypodida.






Tech. Series 17, Part II, Bureau of Entomoiogy, U. S. Dept. of Agriculture. PLATE XIII.



'M














4 ) I








k60 \, 2 ~ o s
4 11















x t






















TIBIAE AND TARSI OF TYPICAL SPECIES OF THE SUBFAMILIES OF SCOLYTOIDEA.
Fig. 1.-Cryphalus asperatus (Cryphalina ), left tibia, dorsal aspect. Fig. la.-Left tibia of same, ventral aspect. Fig. lb.-Tarsus of same, lateral aspect; c, third tarsal joint, dorsal aspect. Fig. 2.Ips typographus (Ipium), left tibia, dorsal aspect. Fig. 2a.-Left tibia of same, ventral aspect. "Fig. 2b.-Left tarsus of same, lateral aspect. Fig. 3.-Corthylus columbianus (Corthyline ), left tibia of same, dorsal aspect. Fig. 32.-Left tibia of same, ventral aspect. Fig. 3b.-Left tarsus of same, lateral aspect. Fig. 4.-M3icracis auturalis (Micracina), left tibia, dorsal aspect. Fig. 4a.Left tibia of same, ventral aspect. Fig. 4b.-Left tarsus of same,1lateral aspect. Fig. 5.- TIebbia dipterocarpi (Webbing), left tibia, dorsal aspect. Fig. 5a.-Left tibia of same, ventral aspect. Fig. 5b.-Left tarsus of same, lateral aspect. Fig. 7.-Crypturgus pusillus (Crypturginae), left tibia, dorsal aspect. Fig. 7a.-Left tibia of same, ventral aspect. Fig. 7b.-Left tarsus of same, lateral aspect. Fig. 8.-Phlmotribus olese (Phloeotribina), left tibia, dorsal aspect. Fig. 8a.--Left tibia of same, ventral aspect. Fig. 8b.-Left tarsus of same, lateral aspect; c, third tarsal joint of same, subdorsal aspect. Fig 9.-Hylesinus venatus (Hylesininae), left tibia, dorsal aspect. Fig. 9a.-Left tibia o f same, ventral aspect. Fig. 9b.-Tarsus o f same, sublateral aspect. (Original.)
N
&/ >
~ \ \\ Wi
7' \
72a
/ Ia
19 Wo)

TIIEADTRI FTPCLSEIS FTESBAIIEjFSOYODA
Fig J.Cypau aseau Cyhlm( ettba oslapc.Fg a-ettbao ae
60taap .Fg Tru fsmltrl set ,tidtra jont dosa ac.Fg 2Ips yporapus lpie), efttiba 'doral spec. Fg. a.-efttiba ofsam vetra asect

Fig.~~~~~~~~~~~~~~~~~~~~~~ 2b-Lf tasso ae/aea set i.3-otyu oubau iotyi ,lf
tibi ofsam, drsa asect Fi. 3,.-Lft ibi ofsam, vntrl asect Fi. 3.-Lft arss o
sameC laea aset Fi.4/1rcsstrls Mcaie) ettbadra set i.4
Lettbi fsme etalapc. i.4.-ettrsso amltra set.Fg .-Mbi
diteoari Wbbna) lfttbi, osa apct Fg 5.-et ibaofsae vnta apet
Fig.5b.Lefttarus f sae, ateal apec. Fg. 7- Cyptrguspusllu WrNturime, let tbia
dorsl apec. Fi. 7.-Lft tbiaof ame venralaspct. ig.7b.Li tau ofsm,/aea
aset i.8-hatiu lw(hietiie, ettba oslapc.Fg a-ettbao
same veta2set i.8.Lf asso ae ltrlapc;c hr asljito ae
subdorsal aspect. F~ig.-yeiu eau Hlsnn-)lf iidra set i,.9.L
tii fsme eta apc.Fg.9.-asu sm, uitrl set Orgnl)L




17, N't 11, f Gtw'1.0' U 5 Not 4 Ag4.uhurb. PLA-rF Xiv,















































Tieje ANp TARSI OF TYPICAL SPErjeS OF THE 6URFAMILIES OF SC04YTOIDEA. Mau I-It t1110,40mal ROPWL M 11=rt tibia, ventra 'Oh-LAMUMS Of UmO, lAt8rHIuapwt; 4, 16(ttarlus, dorsal aspwt of
jointa t dw41 aapKt of =Ii-PAighw.)











Tech. Series 17, Part I1, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE XV.



%C









\
121







V i I!i




/ /




tN
13 yJa





























(ill ___TIBIAE AND TARSI OF TYPICAL SPECIES OF THE SUBFAMILIES OF SCOLYTOIDEA.
Fig. 12.-Ilexacolus sp., left tibia, dorsal aspect. Fig. 12a.-Left tibia of same, ventral aspect. Fig. 12b.-Left tibia of same, lateral aspect. Fig. 13.-Bothrosttrnus sculptures (Bothrosternimr), left tibia, dorsal aspect. Fig. 13a.-Left tibia of same, ventralaspect. Fig. 13b.-Left tarsus of same, lateral aspect. Fig. 15.-Camptocerus xneipcnnis (Camptocerin ). left tibia, dorsal aspect. Fig. 15a.-Left tibia of same, ventral aspect. Fig. 15b.-Left tarsus of same, dorsal aspect. (Original.)










Tech. Series 17, Part 11, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE XV1.










'I, ( rt, I








16b 0


















z
Aq



A



17 b

4 g:

Aya 17a .17










T1131,1E AND TARSI OF TYPICAL SPECIES OF THE SUBFAMILIES OF SCOLYTOIDEA.
Fiv- l"l- ScolyMsscolytlls (Scol vd11:19, left tihi;t, dor,,:d aspect. Fi-. Na.-Leff, Oda ofsame, velitt'all
I'j-, 161), Lell, of.' 1111v, dor' '11 '1' Jwcl. Fig. 17.- Scolytopla/ypij, sp. ( ;colvtoplat.vlell, I il)i:i, dov' al ;Lspect. Vi -. ]-a. Left I ihia of salne, ventral aspect. Fig. l7b. Left
kit-11 of (Iol ;Il '1- pvcl. viv. I". -1,10YPIS (.111indrus left tihia, (Jorsal aspect.






PRELIMINARY CLASSIFICATION OF SCOLYTOIDEA. 179

L "G S.
There is a wide range of variation in the form, color, scuIl)tlre, and relative proportions of the coxa, trochanter, tibia, and tarsus of tIll(e anterior, median, and posterior legs. (Part 1, figs. 1, 3, 26 (..a The anterior tibia and tarsus are o( special taxon()mic iml)()rtance ill distinguishing the primary and secondary divisions of the sul)erfanily and, to a less extent, in distilnguishling the primary ()r minor groups (f the families, subfamilies, and genera. (Ps. X. XII-XVI.) Tihe variation in the tibia is from a simple, coml)presseI slighty (lilate( form with the outer margin serrate, as in Hpothe;.aus, to) a sh';rt, broad form with parallel, smooth margins, as in MIrtacis and Scolytus, or broader at the base, as in lVebbia an(d Hypoborus, an(d to extreme and odd forms as in Platypus. The character of the vestiture usually conforms to that of the body, such as scales, barbed hairs, and simple 'lairs, varying in distribution and density on the ventral and dorsal areas 1id the margins. The sculpture ranges from smooth to imbricate and from irregular rugosities to prominent ridges, the latter reaching a maximum development in Platypodidae. The tarsi vary in form from slender to stout and the joints in relative lengths, widths, and vestiture. The' third joint varies from simple to emarginate and deeply bilobed, with the ventral surface ranging from nearly glabrous to pubescent and to densely padded, which latter extreme is found in Phloborus.
ELYTRA.
The elytra, or anterior wings, are exceedingly variable in form, vestiture, and sculpture, ranging from the simple types with scales, fine punctures, and obscure strie which are not impressed, as in Hypothenemus, to the forms with hairs and with distinctly impressed
-iae and elevated interspaces, the latter with rugosities an(l rows of punctures or smooth and without punctures; the base frOm plain to strongly elevated and serrate; the sides from parallel to converging posteriorly or strongly rounded; the dorsal area from flat and straight to convex and strongly rounded from base to apex; the d(leclivity
f-o.n plain, steep, and convex to retuse or armed anad strongly oblique from base to apex, and the side margins from serrate to straight or emarginate. With all of these almost endless variations and their different combinations o()f elements there is available a profusion of
*:haracters for the definition of groups of genera and species.
POSTERIOR WINGS.
The true functional wings, as pointed out by Nilsslin (1911), are quite variable in form, proportions, and character of the venation and represent two specified types, one with and the other without a Figures 26-29, Part I, represent the reverse faces of the right instead of the left tibia, a mistake which was unfortunately overlooked in the manuscript and proofs.






180 I'HE SCOLYTID BEETLES.

a basal lbe. The writer has given considerable attention to the study of the wings of the Scolytoidea and other insects, but he has failed to find( any constant and readily recognizable characters in the Scolytoidea which appear to be of sufficient taxonomic value to justify giving them special attention. If there is any particular line of progressive modification in the wings it is to be found in the subfamilies and minor groups, in which the range appears to be from a simple type, like that of Hypothenemus, Cryphalus, and Crypturgus, with a narrow, simple base, long fringe, and simple venation, toward a broader base, lobed or not, and with an increasing number and complexity of veins. The writer realizes that the complex type of venation is generally supposed to be more primitive than the simple type with few or no veins, but he is by no means convinced that this is the correct interpretation as applied to the wings of all insects. The wings in different orders of insects may be, in spite of the prevailing opinion, the result of independent origin from simple types of primitive winglike processes, and their evolution may have been influenced by two primary factors: (1) A dominant tendency to perpetuate and promote lines of modification peculiar to and in conformity with the dominant morphological characters peculiar to the order, and (2) adjustment of this modification to the peculiar mechanical needs of the varying related forms, with frequent examples of parallel modifications in unrelated species.
In Niisslin's table (1911, pp. 302-304) the wings without basal lobes are found in widely separated genera, representing, according to the present writer's classification, two families (Ipide and Scolytidw) and five subfamilies, while the wings with basal lobes are found in five subfamilies of the Ipida. It is evident that whenever the wings are studied in their relation to other of the more important taxonomic characters and characteristics of the species, the variations noted by Nfisslin will be of considerable value in the definition of minor groups of genera and species, but the difficulty of spreading the wings and securing good balsam mounts wiUl preclude their general

ABDOMINAL TERGITES.
The general character of the abdominal te.rgites is shown in Part I, figures 22, 23, and 24. tile there is considerable variation in the first to sixth telrgites, inclusive, in the same individual and between in dividuals of different species, the seventh and eighth are the ones of special inpimortamnce in the identification of the genius or sex. According to Nilsslin (1911), who examined 16 genera, the eighthll tergite lnot covered in either sex in 11 general, and is exposed( in the 11111ae, an oed cov Ied in thi female in 5 genera. The writer has found






PRELIMINARY CLASSIFICATION OF SCOLYTOIDA, 18

the eighth to be unicoveredl in both sexes in tfire' genIera. It 1C() Ve i1 the male and covered in the female in 18 gelera. and c(ov'tr'd in both sexes in 3 genera.
According to the writer's classification, the 31 getne'ra illn which species were examined( by Nisslin anid the writer lepre-eIt t he following subfamilies:
TABLE III. -A bd0w tual tritq in the sabf, ulits ff Scale/1id(i i i, wi, Npc r urr e C Jineitd by \'iss/ii and /!/u a '

ighlh er- E ig t r- igih lerSubfamily. vie ei' iii in t i l
ered inl t ere ill e Ii eres
sexe. p. i female ..

Cryphalinm ...................................................- 1 ..............
Ipinae .............. ---------........................ 2
Corthylinm .................................................... --M icracinae ............. .. .................. 1
Crypturgina .........................-- ------- ....... 2 ...........
Phlkeotribinam -----.....-- ------------- ...... ......... .... ..... ......
H ylesinin a ............--------......................... .......
Scolytinae -.....-------------------------------------------- --Platypodina ------ ----.............---- ------------ ---- ------------------ 3
Total .............-------------------------------------------- 1....2 17 3

From the foregoing it will be seen that the characters of the seventh and eighth tergites are paralleled in widely separately genera and subfamilies. The writer has found that the eighth tergite may or may not be exposed or covered in the same genus or in individuals of the same species, especially in Platypus, where the eighth tergite is of the same or similar form in both sexes and may be covered or not, depending upon the expansion or contraction of the abdomen. It is evident that a much more extensive study of these elements is necessary before any conclusions are warranted as to their taxonomic value or lines of progressive modification. In a number of genera the seventh or eighth tergite, or both, is exposed beyond the opex of the elytra and is either oblique, declivous, or vertical. The ninth and tenth tergites are absent as such or are modified into elements of the genital organs.
ABDOMINAL SPIRACLES.

According to Nisslin (1911) an(ld Fuchs (1912) the number of functional abdominal spiracles (stigmata) ranges from five to seven. The larve and pups, so far as studied by the writer, have eight.
The spiracles are variable in structure and doubtless, upon further investigation, will furnish excellent taxonomic characters. The writer, however, is doubtful as to the phvlogenetic significance of the variability in number. The genera given by Ntilsslin (1911, pp. 2-5) and Fuchs (1912, pp. 13-14) which are represented by species having






182 THE SCOLYTID BEETLES.

from five to eight spiracles fall into the following subfamilies as recognized by the writer:
TABLE IV. -Abdominal spiracl, s in the sub familis of Scolytoidea in which species were e alined by Nisslin and Fuchs.

Subfamily. Eight Seven Six Five
spiracles.a spiracles. spiracles. spiracles.
Genera. Genera. Genera. Genera.
Cryphalina ......... ..... ....2 3 2
Ipi ia........... ......................................--------------------------------------------.... 1 ........................
- -orth ina ..------------------------------------------... ... ............ ------------1M ieracim e ............................................. ............ ............ ............ 2 .. .
Crvpturgina ........................................... 1 2 ............
Phblo otribine ................ ......................... ............ 1 1 4
H iC esinin a- ............................................ 1 8 2----------------------- -------CrpuMni------------------- -------1- --- ---1-Choribn -------------------------------------- 2------11-Iy iia' ------------------------------------- ------------ 8 3
Scolytina ........... ........................ ............ 1 .
To t al--------------------------------------- ------------ 15 12----- -----Total ........................ ................... 2 15 7 12
a The eighth spiracle is rudimentary.
In the genus Hylesinus (Fuchs, ibid., p. 13) there are from five to seven spiracles with the sixth and seventh rudimentary, while in Dendroctonus and IIylurgops the eighth is rudimentary. Doubtless if the number of abdominal spiracles were determined for all of the species, some good evidence would be furnished as to lines of modification.
ABDOMINAL STERNITES.
The abdominal sternites I and 2 are fused and concealed in the coxal cavity, 3 to 7 are exposed, and the eighth is covered by the seventh, while the ninth and tenth evidently are represented by the genital organs. (See Pt. I, pp. 25 and 38, and Technical Series 20, Pt. I, Pls. VII, VIII, and IX, as also the discussion of the reproductive organs in the present paper.) The exposed sternites are quite variable in the1 different genera and species, and certain characters are of value in designating minor groups of genera, but few, if any, are common or peculiar to a subfamily.
The m(iodifications range from the simple type found in the Cryphalinll to the steep, excavated, armed, and odd forms of the Scolytida aniid Platvypo(litdl. There is a wide variation, which is apparently of specific illpI)ortancie, in the eighth ventral segment. The palpi of thie 110inth1 ventnlil (segment (Nfisslin, Fuchs, and others) found in the females of Scol!/1tus anl(l Iylestnus, may after all represent tihe tenth tergile or sternite, one or both of which may be represenlte(l by the (ovipsit( or as in certain (Ciurculionoidea (Pissodes), Cerambycoid(lea (t' //c), and iimany other insects. But this is a matter requiring Iliur'e COil)R'el siv li !l vest ig l ()11.
S'Ti I) ULATING ACCESSORIES.
'ITe strilulahting ac(cess()rl-s have not )een investigated by the writer in mniy genera but1, tey appear to be confined largely to the scvcItl abdominal tergite anl the inner subapical area of the elytra






PRELIMINARY CLASSIFICATION OF SCLYTOIDEA. 183
(Part I, figs. 23, 31, and 33) ,and to the anterio(r largil of the pronotum and the posterior dorsal area of the head.

INTERNAL ANATOMY.
Considerable study has been made by Lindemann, Nilsslin, Fuchlls,
and others, of certain clements (f the internal anatomy, especially
the proventriculus of the digestive system ald the llale a fml
reproductive organs. It is evident, however, from a review of the








) """( --L L


......J/ <.
J/


FIG. 98.-Proventricular plate of Ips A0)
emarginatus, inner
aspect: a, Entire plate; b,divided an- FoIG. 99.-Proventricular
teriorplate; c,poste- plate of Scolytus scolytus: FIG. 100.Mastirior or masticatory b, Divided anterior plate; F. 100.-Mastip late; d, median d,mediansuture; h,lateral catory plate of
longitudinalsuture; margin; gl, apical lami- Crotars us lee, sutural teeth; f, nate teeth of posterior conti: c, Mastimedian transverse plate. (Original.) catory plate: la,
suture; g, transverse apex and lateral
or apical teeth of an- serrat ions o f
terror plate; h, lat- results that as a sufficient basis for masti ator y eral margin or mar- teeth. This igginal suture; i, lat- general or specific conclusions a far ure should be
eral or masticatory gvie\wle in a reteeth; ia, closing more comprehensive study is necessary, verse I posit ion
bristles or teeth; j, in order to recfemora of the mas- ognize the eleticatory teeth; k, voted character
femoral teeth or DIGESTIVE SYSTEM. of the iedin
ridge; 1, mastica- longittidinal
tory brush; n, mar- area. (Oriinal.)
ginal bristles or The general type of the digestive sysfringe. (Original.)
tem is shown in Part I, figures 35 and 30, for the
adult and figure 43 for the larva. Lindemann (1876, pp. 145-169),
Niisslin (1912, pp. 85-87, figs. 135-143), and Sedlaczek (1902, pp.
241-263, figs. 1-20) show that there is a wide variation in some of
the elements and especially in the proventriculus and the median
and posterior section of the midintestine, but to what extent these
variations are of value in taxonomy has not been determined.
PROVENTRICULUS.

The proventriculus (figs. 98-100; Part I, figs. 35-38) is of special
interest, and the work of Lindemann, Fuchs, Nisslin, and others
has contributed much valuable information on the structural elements.







184 THE SCOLYTID BEETLES.

Ther-e is a wide range of variation in the proventricular plate s and their armtutres, such as the various divided and undivided forms with and without the brushs" of fie masticatory teeth. These variable forms appear to be of considerable taxonomic importance 11ei cormrela ted with other internal aiid( external characters. Th eclassificatioai proposed lby Liiideiilann and NUlSSLmn., as based on the s4tuctural characters of the proventricuilar plates, with a few p)lainly evident exceptions, correlates in a strikingc manner with the external characters adopted by the writer for the major and minor groups of genera. Mhenm the principle of parallel modificaItion is considered, the genera which seem to be out of place in the classifl------ -- --It
Fw w (nd//Jonu vals Vein
brno an iiibtnusee e so
the~ ~~ ird e -dctieogn. e e-F .12.A17/lissv(2. hiil sCO
ininolv Nmi~icr Divisins 2,3, 4, p. nje ts ofmi I !er(,pr (Itcieogn sofr








REP(MCTVE ORIAS

-f t

thelle rerodlictive gn.Setr w 0 hou acci htnisee
1W2-i d 1 11d (O ig i) 1) nea fv Iinraology f 1)so1, p.1 219. Oigna. catioii 1)ase ( 111o pIro 1entricular1 chrctr aln wI whe correla/ 11( 0 1 '/( I); l '101 IIt heds


TIIF'~~~c 11 oPII )fLV 01IA M F''erl M LE

II ~ ~ ~ ~ ~ ~ ~ ~ ( II )rod. av oraso.h ae(is 0-1)hv en
SI~~~~~~~~~~ itic 7,-l :;2uc( 115svililvst(~05U lW
C,6 i
'1'x ~ m F V. Nou nue, / ru'e sl i i...f...........dU I UC rqinsb911 20 4~krs
_Nu 12 2r
Flwh~~Yet ...... .m e ....... 1912 302
\- 1912 2ar 2ul-os~ts rp





PRELIMINARY CLASSIFICATION OF SC()LYTOIDEA. 185

In addition to the foregoing, the writer, duringg the yea s, f ro I 892 to 1912, has stu(lied the male re)r()(luctive o()rgans of (s species, re presenting 43 genera. The total spel)cies studied bVy all authors, without duplication, is 147, representing 57 genera. ..........
The reproductive o()r- .
ganiis of the male represent four primary (divi- as- (
sions orelements: (1) The ,.
posterior chitinized di- a-' 1
vision (fig. 102), (2) the 2iposterior membranous division (fig. 101), (3) the median division, and (4) c-the anterior division. (See terminology, pp. (
192-194.) a
POSTERIOR ELEMENTS.
The posterior chitinized elements (division 1) consist of four primary sections, (a) the body, (b) the end plates,
(c) the tegmnien, and (d) the spicule. In addition to these more constant elements there are (bl) the seminal valve and
(2) the seminal rod, both of which appear to be more intimately associated with element b thanlwith elementa; also, there are (e) the connect- ,/-,
ing membrane and (f) the muscles. From a /
somewhat comprehensive study of the chiti- / / 11 I
nized elements in the
FIG. 103.-Ips (, rfrginalus: ('li inous el ments of mle reproscolytoid l)beetles in cornI- ductive orans. I. veniral aspect; II. lora1 apect. See pt terminology-, Division 1, pp. 192-193. (Original.) parison with those in other insects it seems plain that, so far as these l)eetles are concerned, the chitinized parts of the male reproductive organs represent elements of the ninth and tenth abdominal segments, either as direct modifications of primitive sclerites or as ind(lependent developments





186 THE SCOLYTID BEETLES.

from the same fundamental source as that from which the various segmental lobes, sclerites, and appendages have developed. It
would appear best to refer to the chitinous element of the copulatory apparatus as repreasenting certain segbe- -mental elements
ad .. rather than to asd sume that they have been derived through
Sd modificationfrom
.-c sclerites or appendages which had ex1ca / listed as such in a .
FIG. 104.-Pityophthorus sp.: Chitin- primitive ancestor. ous elements of male reproductive *
organs. See terminology, Divi- It is quite evident
sion 1, pp. 192-193. (Original.) that element a rep- X
resents the tenth sternite, b the tenth tergite, c FIG. 105.-Pityophthothe ninth tergite, and d the ninth sternite, while bl rus beUus: E nd plates and seminal
and b2 appear to represent elements of either rod of male reproductive organs, latthe tenth tergite or of both the tenth termite and eral aspect. Note
9 contrast between
tenth sternite. It might also be well to con- this and fig. 104.
See terminology, Disider in future investigations the possibility of vision 1, pp. 192193. (Original.)
their representing the tenth pleurites or even an additional eleventh segment. The 6a ', wide range in the variation of these elements, the absence of some of them in di certain species, and the joining or fusion
of two or more in other species render a i: it exceedingly difficult properly to in,i terpret the primary and secondary elements, especially in the more complex and in the apparently simple forms. The body, or element a, is present in all pe ie.;. It is more or less distinct from the other elements and is nearly always suggestive of a modified sternite; oL Whe femora (al) appear to represent the prodluced posterior angles, or apodemes, of a typical abdominal sclerite, and the Fu,. (.Icrais suturais : Posterior lateral folds (a2) appear in some cases to elwfienls of male reproductive organs, .
in ps, where they resemble enld plates and were so identified by l ,indemann. The function of element a is that of a sheath or tube for the ej aculat ory sack (2a) and for the seminal valve







PRELIMI-NAM' CLAS61l'ICAT1(")N OF 187

































C-3 Zi

t4i














r-Z
zz




188 THE SCOLYTID BEETLES.

(bi or the seminalrod (b2), or both, as the case may be. The end plates
(b) are commonly present. They are sometimes fused with a2 but are more often separated or more directly connected with bl or b2.a The end plates proper appear to function as accessories to a in forming the sheath or outer tube; bl may function as a valve to close the seminal duct while muscular or blood pressure is brought to bear on the ejaculatory sack to force the seminal fluid into the copulatory pouch, or they may function, as indicated by Lindemann, as a furrow or troughlike support for the posterior end of the seminal duct. The end plates are subject to great modification, from simple chitinous pieces, as in Pissodes, to the more complex structure with many parts, as in Dendroctonus (fig. 107), and especially Hylesinus, or into a long slender troughlike rod, as in Ips (fig. 103), a stouter rod with apical dilation and a long flagellum, as in Xyleborus, or a brushlike form, as in Micracis (fig. 106), and Xylocleptes. The function of the slender rod or apical filament is not known, but it may serve to conduct the seminal fluid directly into the spermathecal duct.
When we consider the enormous range of possibilities in the modification of tergal and pleural sclerites, as manifested in the tergum and pleura of the metathoracic segment, we can readily understand that the most complicated and complex copulatory apparatus yet found in insects is comparatively simple and that the possibilities of further modification have not been exhausted.
The tegmien, or ring (c), is generally present but may be obscure or absent. There is a wide range of variation, from a simple and ventral plate (Scolytus rugulosus, fig. 108) or fork (S. quadrispinosus, fig. 109, and Crossotarsus, fig. 110) to a continuous simple ring or band (fig. 102), and from a plain or forked dorsal piece to a forked or plain ventral piece. In nearly all cases it functions as an apodeme for the attachment of the primary and accessory muscles for the posterior extension and movements of elements a and b. The sections of the various forms of the tegmen may be referred to as (ci) the posterior section, (c2) the median section, and (cd) the apodemal process. Sect ion cl mInay be either dorsal or ventral; in whichever case section c2 w ill ocupy tilhe opposite position.
Iie spicule or rod (element d(1) is usually present in a more or less di-it 6lform which may vary from a curved forked rod to a simple r)i,' anl in its various 1moditications and functions nmayv occupy a dorsal, subla cral, lateral, or subventral position. The sections of t1he various forms may 1)e referred to as the anterior section (dl) and le )olsterioIr section (d2). It functions as an apodeime for the attach, Vorh,,ff (IS9I) and N iusslin (1912) considered the end plates as belonging to the 11(1,.







PRELJMINAH V CLASSI1,1CATION OF SCOLYTOIDELA.18

mont of the p~iiiiary and acc(c-sory iiu'scles for the14 ret rac tile Ino -1N0 mlent's of tlu tube)4 ((t amt~ b)). The muscles (c) tare moi-e ow less coml)icated and Variable in1)ze iiumber, and( att a(1111e11s. li oin ca114(ses" ,Is III. IDcrdrOolloiis. tiit
























'liJ,



FIG.108-Scoytu ruuloss: osteiorele entsof IG. 09.Scoytu8quaris
malereTrouctie ogan. I.latralaspct o piosu: Po Ieior ele

body; 11, laea-seto oyadacssre, iet fiierno
in it: IIboy ccesoie sewaed tr- iv ogar. LtejJ~~pO
minoogy Diisin 1 pp.192193 (Oigial. Seeter inoogY Diii2
1, pp 9 -9 O iia.
extesorand etrctie muele are prminnt, he orme (4 at


taelie/ potrolIoteaneiregIfeeen ,wietesp

plemetary usele W) ae. atachedanterorly o thposereg



of an potiorl toteinrsrac fteegt sen ,a i
(edocu or toteatro eto (f lmncadteegt
59020-153!





190 THE SCOLYTID BEETLES.

tergite, as in Crossotarsus. In Dendroctonus the retractile muscles
(<2) are attached to the anterior end of the spicule (d) and to the basal angles of the body (a), while in Crossotarsus they are attached to e2 and to the sides of a ventral groove in a.
The connecting membrane (f) is very difficult to locate and follow to its primary connections, but if it could be accurately traced it would doubtless furnish good evidence as to the proper assignment of the chitinous elements to their respective tergal and sternal origins, unless, as is the case with muscles, the attachments are changed or even reversed to harmonize and economize the requirements of function. The connecting membrane between the posterior section of element d and the eighth abdominal sternite in Dendroctonus seems to furnish quite conclusive evidence that the spicule represents the nintlh sternite.
ANTERIOR AND MEDIAN ELEMENTS.

The anterior (4) and median elements (3) of the male reproductive organs have received special attention by Nisslin, who bases a classification on the length of the ductus ejaculatorius (2b) and the character of the testes (4b), seminal vesicles (3), vas deferens (4a) and mucous glands (2c).
VARIATIONS AND COMBINATIONS OF THE ELEMENTS.
Various combinations of the elements of the copulatory apparatus are found in the species of allied genera. Quite a wide range of variation is also found in the character of the elements in the species of the same genus. Even species which in all other respects appear to be closely allied have very different characters, either in the form of one or more elements or in different combinations of the elements.
In Division I of the family Ipida the absence of the seminal valve and the presence of the seminal rod appear to predominate. The valve, as a definite part, is absent in 21 genera and 52 species and present in 10 genera and 16 species. The rod is present in 25 genera and 55 species and absent in 8 genera and 14 species. Both the rod and valve appear to be absent in 6 genera and 10 species, representing 4 subfamilies, and both are present in 10 genera and 15 species, reprosent ing tlhe same four subfamilies, and especially in Corthylinas. The striking feature of the Subfamily Ipinmi is the apparent a separation of the femora from the body, esI)ecially in Ips and the closely allied genera. Ii Pityopltldhorus (figs. 104, 105) they are found to be fused with the body in some species and sepl)arated in others; within still ,t her species ti here is a ,-upp))lemiont ary band (a3) (onniectinlg them at ,or 1iear iw( 1)ase.
writ r hlls f, d i ht t lie Ifra are connectedd if) the hody by ligaments.





PRELIMINARY CLASSIFICATION OF SCOLTOIDEA. 191

In Division II of the Ipidae the presence of the seminal valve and absence of the seminal rod predominate. The valve is present in 20 genera and 44 species and the rod is absent in 20 genera and 43 spev io i e -1










cis Th av sasn i eeaad4sece n hrdi
II













cies. The valve is absent in 2 genera and 4 species and the rod is present in 6 genera and 12 species. The combination of rod and valve is found in 4 genera and 10 species.






192 THE SCOLYTID BEETLES.

Inl the family Scolytidve there appears to be a wide range of variation. In Erineophilus schwarzi Hopk., of the subfamily Hexacolina, the rod is absent, the valve present, and the femora are long and slender. In some species of the genus Scolytus the body is greatly modified, somewhat resembling a seminal rod. The valve is absent and the fomora are rudimentary in S. muticus Say and S. qadrispinosus Say (fig. 109). In S. rugulosus Ratz., however, (fig. 108) the femora are long, the valve is represented, and there are some additional parts; in fact, all of the elements are radically different from those of the other two species.
In one genus and one species of Scolytoplatypodidm the rod is absent and the femcra are large and very broad, differing in this respect from anything yet observed in the entire superfamily.
In two genera and five species of the subfamily Platypodinm the body is long and slender, but without the spicule, end plates, seminal valve, or rod, and the femora are represented by short hooks at the basal angles of the body. The tegmen is present in the form of a fork.
A study of the available data relating to the primary and secondary elements of the male organs of reproduction shows that within the families, subfamilies, and genera there is a very wide range of variation and that the same or similar elements individually, or in various (combinations, are often paralleled in su ecies of widely separated genera and subfamilies, so that their principal taxonomic value appears to be restricted to the separation of species and minor divisions of the genus.
It appears that if there is any line of progressive niodification within the major an(d minor groiips,, it is from a simple form without seminal valve, semIinal rod, or end plates, as in some of the Cryphalim and in the Platypod(inW, to the most complex forms with or without the valve and with or without the rod, the rod( reaching its highest devel()lipment inll Xyleborus, Dryoctres, Lywantor, Ips, and( allied genera; while the valve without the rod reaches its highest (develol)lm)ent in liyh 'i and( allie(l genera in the Ilylesinin.a'
TEMImmO.IOY F THE i, it)OCnriv E O(I.ANS.
In tlhe followillo list it is inlitenlded that the numbers and letters
(ih ei(~inat(e the (lelielits of the re)r(loductive organs r1)11 11 1 IA) ,1 ai thors,
r'ath&'r thali nales, causee the names pripsed by different authors ila(lilg tlhe writer, do lot agree in all cases in designation or lilt (,i ret ati in.
h10al' l.da101 (d.qa .

Illl f l 1Figs. l ll.l 11I
i1i tii l, I 0, Ie l o Illi i li ls I vision
I i i inn :'. Mlelian livisio)n.
I i t i i, n 1I. A\ n| t, ri o)r liv is i o n| .






PRELIMINARY CLASSIFICATION OF SCOLN"I't)JO111A.


a. Pool X-.
(11. Bool apodell '(-; ( fellifwa).
(I M. [)()(Ielli'( I I i"'.11 luell I .
a Lmel-A fohk.
(12(1. Lalel-A ( Iccez'- ( I-%- N i'- lill').
stipplellwilizir y 1)()d mm-, 4,1 -1- h'twl.
a Apicill orifice or ejacul, tol-N,
(t) o i i -iw area (w P W('1'-:. b. 1. Ald
bl. valve awl
r(;(L
'\J)iC 11 1111111 Of b ".
b-4. Apic il of
1)5. Solisory
b ( Apical 1()I)e.

cl. Po t( rioi or tbr- .it -(-,ctioii.
C2. Antul-i('I' ()r

(7. piciile.
di. Anterior -(vtioii.
d,!. Posterior (,(-tion.
d;-'(',. Lateral apodenie ()r 11 '0111 :'
(/,)b. lAiteral b-irb. e. Muscles.
(,/. Extensors.
e--9. Retractor-,.
e,,3. Suppleiiiejit-arN.
Connecting mertibraiie. g. Ligament.
1)ivisioii 2.

2a. Ejaculatory or pra-putial sac.
2al. Chitinous base, or tu e. ,?b. Seminal duct. ,2c. Alucou glands.
Division
Seminal vesicle.
Division 4. 4a. Vas defereii,,. 41). Testes.
Fciiiat'e R(produciii( Oiflo s.


Division 1. Posterior divisioji. Division 2. Anterior division.
Division 1, Ia. Val-iiia. 11). Bur,, ;a copulatrix. iba. Accessory sac. 1c. Unpaired oviduct. 1ca. Apex and apical orifice of oviduct.






194 THE SCOLYTH) BEETLES.
]d. SperinaLheca.
1c. Spermathecal gland.
1f. sealinal (Illet.
1 (1. Cement ,,Linds.
11,, Chitinou- plates.
Division
Pair(,(l viaductss .

CLASSIFICATIONS BASED ON THEREPRODUCTIVE ORGANS.
In the classifications of Nfisslin (1911), Fuchs (1911), and others, as b,'L- ('d oil the male reproductive organs, we find, as we do in the classi.Ica fictions based on the elements
ib of any single organ, that genera
.91 and groups which are plainly not closely allied are brought to(rether and those which by
_ih the majority of extern,al and internal characters are closely allied have been placed in widely separated divisions or subdi-,-lsions. When, however, the f acts of parallel modification are taken into consideration and the principal elements are correlated -vN-itli those of other ore7lcrans the resultsare quite different ail..d the true taxononiie Fir,. III.- DindT000pus m7(ps Female reproductive value of the elements is recocrOFIIIATI- I ce t(,rniinology, Divj-:j()n 1, pp. 19:)-194. Z6riLiwll. I nized. It is evident that a
stu(I-N, must be niade of the male or(rans of reproduction in it inuch larger muliber of species of all available (renera before the true taxo11011licvalue of ally of theil. elenlent-, c.oi be determined land correlated.
(1912), w1lo, lias (rl\,en tliesubject of the female reproductive orgalls (J i(r. I 11) of Scolvtlda late considerliltion, calls attention to the t'lNollolilic import le (rollifill or(r,111., jil ill(r the
allCC* Of ttle f(,Ill<,
Ild l'oJvpJ1,1(rl, (-)f tll(, or(J(,l- ('oleoptent 1.11(1 ill (11,4111(rilisliiii,"r flic iiborder Iflipicliopliont, which he claiiiis is peculiar iii hL-6ng Only tw(i p"lir, of twan;L.
rPw '11)- cllce of a trile o6positor i-.,' (IPP'l 111 lt)IN- colninoll to ,ill CoIYtoid heetle-,, ilthougli ill soiiie spccl(- diere tire ril(Ilillelitto-Y palts
M ()I 11cl. IZIlYT101opliora all(I G)Ieoptent belolig to flie o6positor,
I'lle palf)i, WJliC)l lltt\-(' ]WO11 rollIld M lk- ill SCOIIIhIS "Illd
If,//f s /'/I /IN. T he pl-c-'elicc (4 p'llred or sill(rle cellient, (rJ-i11(J_; t() 1w ill illlportallL 'alld Inol-c w. lc., ., peculi'll. clement ill t1le Scoly'11HIM11-r1l it, is "'Lld to be ah-wilt ill Scol.11his ,Lll(l P"I.Imporli II Its





PRELTIINAHYR CLASSIFICATION OF SCOLPVTII)E.A. 195

in other Rhynchophora. The bullrsa cop)iulatrix, according to Niussli, is present inii Scol!/ts, H?/lesiLn s, Pol!/raphus, ('ryptulrgs, and IIyoborus, much less evident in ('arphobor s, Pityophtlorus, Dr/ocats, Taphrorychus, and Lynmantor, and ob)scure or absent in ('ryph l us, Xyloterus, Xylocleptes, Tlwit ilu rs, Ips, and Pit!/ogenets.
Conclusions as to whether or not the presence or absence of a given element is primitive in the Scolytoidea, as based on morphological interpretations, are becoming much less reliable than formerly because of the frequency of parallel origin or disappearance of adaptive elements.
N tisslin's (1911, pp. 333-338) classification as based on the female organs of reproduction relates primarily to the presence or absence of the cement gland and to its varying forms; secondarily, to the presence and character, or the absence, of the bursa copulatrix, and the character of the spermatheca and its seminal duct.
When the characters of the female reproductive organs as given by Nisslin are correlated with the external characters on which the writer's preliminary classification is based, Scolytus falls into the subfamily Scolytine; Hypoborus and Thamn rgis into the Micracine: Crypturgus and Carphoborus into the Crypturgnme; Polygraph ~us into the Phleotribine; Pityophthorus, Pityogenes, and Ips into the Ipine; and Xyloterus into the Corthylinm; while Ernoporus, Cryphalus, Taphrorychus, Lymantor, Dr!ocoetes, Xyleborus, and Xylocleptes fall into the Cryphaline.
With a more comprehensive study of the female organs in numnbers of species representing all the genera it will evidently be found that there are some excellent taxonomic characters in the primary elements and in their lines of progressive modification, which in combination with other internal and external characters will be of special value in defining groups of allied genera and in indicating relative positions of the groups in the classification.
SECONDARY SEXUAL CHARACTERS.
There is a wide range in the types and position of the secondary or external sexual characters, such as difference in the size of the body, as in Hypothenem us, Ste phanoderes, (occotrgpes, X! lebor us, and allied genera, and the radical and contrasting differences in the structure, vestiture, and sculpture of various external parts and areas. The front of the head may be convex and glabrous in one sex and in the opposite sex it may be flat to deeply concave, smooth, and shining, punctured, and with dense and long pubescence or the margins fringed with long hairs. The armature of the declivity and the character of the sutural impressions or broad excavation often vary to a remarkable extent in the two sexes. The scape of the antenna may be stouter to dilated and fringed with long hairs or not fringed. The funicle, club, mouthparts, tibia, tarsus, abdominal tergites, and sternites, in





196 THE SCOLYTID BEETLES.

fact alhnost every important element of the body, may be the bearer of characters for distinguishing one or the other sex.
It would appear that as a rule there is a certain degree of constancy inll the location and general appearance of a male or female character within the limits of a genus, but there are some remarkable diff rences, and even reversals, even in the major and minor divisions of a genus. In DAndroctonus, for example (Part I of this bulletin, p. 73), the females of subdivision A are distinguished by the presence of a transverse ridge on the anterior area of the pronotum, while in subdivisions B, (C, and D this character is not present. In subdivisioll B the elytral declivity is more rugose in the female, in subdivision 'C this is reversed, and in subdivision D there is no difference in this respect. In some genera the pubescent or concave front is a femniale character, while in other genera it is a male character. Other reversals may not only occur in different, widely separated genera but in the same genus. Therefore it is not safe to conclude that because certain characters designate the female in one species this will hold true for the other species of the same genus or for allied genera. This can only be (lefinlitely settled by dissection, which can be done without seriously mutilating the specimen if the abdomen is carefully removed from the body anid the sternites are remounted on a card point after the examination is made. The presence of the chitinized spermatheca in the female and thie presence of the chitinized elements of the postertior section of the male organs are sufficient to settle the point, even in old dried specimens.
The lines of progressive variation or modification in secondary sexual characters appear to range from absent and obscure to common and prominent.
THE PUPE.

Comparatively very little study has been made of the pupe of even our common species of Scolytoidea, and until a comprehensive study has been ma(le it is scarcely necessary to mention the characters in connection within general taxonomy. The description and figures of t hle pupa of Dendroctonus valens (Part I, pp. 53-57, figures 37-38; synopsis, pp. 73-74, and descriptions, pp. 81-152) Aill serve as an example of thle general typ)e, while the figures and terminology will srv( as a gui(le to future study.
Il l, writer h is exanilmed I the pupw of quite a large number of No'thI Americ(an species an(d finds that there is quitee a wide range of variation, but io() attempt hlas been made to analyze the taxonomic charters except in tle genus Dendroctonus, in which the form of thle h(a(d a11(l tlhe character of the frontal, tergal, lateral, pleural, cnua11, aI( f, nral spi)ies serve as important characters for id(lentificat ion a(nd classifi( ion a n(, when correlated witt the adult charac1ers, give 1h, s m ( r si iilar t iXO(milic result.






PRIELITINAY ('IASSI FI'Ai'IoN O ()1,'IiII~\ 197

T I 11, 1 A RV

TLhe stt-iliutund 1il ni1(1 1 )I )1l( gica 1 eieiiiei its otf the fiaiv id M;ofIn1~droctous ar-e sho wnI ill Pailt I fi m res 39-43. til( Pra t ine \ II f i( oi IeS 1-231, andi([ese, witlit t lie terrtiii1oog' arid wIsrjtInxill Sei'vee as a guide to a, greatly iHee(I ful hfer. situdy ''Of le lar-valst;2{ before we can~ have a basis foi- (hit('iiis as to I hir irupo' a ill taxononiV. 'Ilie wi-t (H' has exa itite(lI tlielve of, qite a large numbltler' of species, but, it) dl{t:,iIVdh(l yt has lw~eil Imte 'xcet' ill .Dendroctol a is and [Of t Ie a, 1) 1i -111 a f I e l11)cI- () f sj 1)(', I es in 1)'1 Ia -' 011 'ra (11opkilis, R. 00~, P~le 1). [his ha.1s Ibeelt stiflicient .Iovee, indicate the wide rang)*e of var-iationl ill, sone (d t lie (blelt and( thew great imjpot'tallte of' a, noi'eoiflliise klloxie(e od ie slib1)j(( In Dendrocton Ls the ii V Han t cl Ut HI( ters av i'eI 1 il tw e (<1tlta "11 niiith tabdoiinl. terigies al t l( fit(1teeth t(Caff)eo p~rog'ressive iniliicatioti is found iii the 5t'UIIttli'e ai( aurinl tire of the eighth and ninth abdominal tero-i tes fr'( )l i )5 wifft lt( )l1 plates inl Division I afil Division 11, se(ctioln (a' to tim( tunai'rn11ed plates~ Of Section (14 an(l to the alrme(1 plates- ()f stIl)(lliioti D, iielt eorr-lutes so nicely with pi-ogressively inodilied characters' ill thle at! tilts andl in the graller-ies. rPie 1lar'x, of the species of Platy~lpanaid Cro.ssofir, ?s examined by the writer- show rad ical differences i formi anit ill soiVIC of the anatomical elemients,, as, forP example, the la1'li Hi (Ho(pkins, 1905).
THlE EGG..

While the eggs of many species have been observed by the writer, they have not been studied in detail. They appear to conform in general to. an oblong, oval, or nearly g'lob~ular shape, and are pearly white and smooth, with few elements of vestiture or sculpture to serve as taxonomic characters. However, this is a subject worthy of detailedl studlv. The size of the egg in comparison with the size of the abdomen varies enormously in different species. In a species of Cui'plhorus a fully developed single egg, was found to be so large as to occupy alm'iost the entire ab~domninal cavity.

THlE EMBRYO.

The embryol ogy of the scolytoid Ibeetles is another subject which has not received much attention. While the writer feels that there is need of detailed study of the embryo to (determine any adlditionlal facts which may be of value, hie is inclined to the belief that more attention should be given to a comparative study and correlation of characters of the post emb rvonic stages (young to matured larvT.) of a wide range of species in the order Coleoptera, in order that we may know something more of the fundamental facts and be better able to interpret their real significance.





198 THE SCOLYTID BEETLES.
PHYSIOLOGICAL CHARACTERISTICS.
As pointed out in Part I (p. 64), the physiological characteristics are of special taxonomic importance when correlated with morphological characters. The food, social, and sexual habits, character of the brood galleries, choice of host plants, and distribution of genera and species are all more or less rich in facts of taxonomic importance.
GENERAL HABITS.
The scolytoid beetles are distinguished from nearly all other Rhynchophora by their habitof excavating characteristic egg galleries in the living or dead plant tissue. The few notable exceptions are found in the genus Stenoscelis, of the Calandrid, the adults of which excavate a primary egg burrow, but as a rule this habit within the suborder is peculiar to the Scolytoidea. The egg galleries of Scolytoidea are excavated in the bark or wood of trees and shrubs, the roots, stems, and leaves of herbaceous plants, the fruits or seeds of palms and other plants, young pine cones, the wood of barrels or casks containing water or spirituous liquors, etc. Some of the species excavate their galleries in decaying bark or wood or even in the fruiting bodies of fungi, while others confine their work to the bark or wood of weakened, dying, or recently dead plants, and still others prefer to enter the living and sound tissues.
The food of the adults and larve consists of the sugars, starches, and other nutritive elements of their host plants, or of fungi which grow in their brood galleries.

CLASSIFICATION A(CORDING TO HABITS.
Any classification of the families or subfamilies based on food habits alone would not indicate a natural arrangement, as is plainly indicated by the parallel habits of groups of species in widely separated families, subfamilies, and genera. It is true that there are several well marked classes according to habits, such as bark beetles, twig beetlesle, seed beetles, cone beetles, and ambrosia beetles. It is evident, however, that food habits, like many other characteristics 111and(1 structural characters, have evolved along parallel lines in allied as well as in widely separated groups. There are many examples illustrating this principle. The genera Xyleborus, Corthylus, Scolytopl/aty/pus, and Platypus are, according to fundamental morphological elements as well as groups of correlated characters, so widely sepalranle(d 1hat they each represent a different family or subfamily; vet the habit of excavate ,g" their galleries in wood and feeding on SuIb1)rosial fungi is com mon to them all. Between some of those genera 1 There is also a inOre or less constant resemblance in certain miorphologial characters, especially in the hairs and slender teeth of the






PRELIMINARY CLASSIFICATION OF SCO.YToI1EA. 199

lacinia of the maxilla, but this is evidently (due to parallel aaptat ion to similar uses andl not to (o01111m011 origin or l)hylogellt:' (lescelit from a common anl)rosia-feeding anesto.

ood 1 ABITS ()OF TI V. ADULTS.

As a rule the adults obtain their food from the substance in which they excavate their egg galleries or from the fungi growing on the walls of the galleries, but there are numerous examples of special food habit such as that found in Scolytus, PIteleobius, Phleosinus, and Tomicus (see p. 220), which excavate food burrows in the living twigs of their host trees.

FooD HABITS OF TIHE LARY2E.

There is a wide range of variation in the food habits of larve of different species, especially in the character of their food burrows or larval mines. Each species of a group of closely allied species may have similar habits, but, as shown in the genus Dendroctonus, there may also be a wide range of variation and some striking examples of progressive modification in this habit within a genus in which there is a restricted range in structural characters in the adults. In the genus Dendroctonus there is a tendency throughout for the larval mines to occur in groups of increasing numbers from the simple, isolated mine of Dendroctonus brevicomis to closely placed groups in Dendroctonus simplex and D. piceaperda and to the large social chamber of rmicans, valens, and terebrans. (See figs. 73, 75, 79, 88, and 91, of Part I.) Thus the stage in the modification of the larval mine of a given species may indicate, in connection with stages in the modification of structural characters, the natural position of the species.
In the ambrosia beetles the larve of some species and groups of genera, as Xyleborus, Stephanoderes, and Crossotarsus, live in the primary galleries in direct association with the eggs, larve, pupe, young adults, and parent adults, while in the subfamily Corthyline, the genus Scolytoplatypus, and at least some of the species of Platypus, the larve occupy separate chambers in the sides of the gallery, these chambers not extending beyond a size sufficient for the accommiodation of the body.
PUPAL HABITS.

Considerable variation exists in the habits of the pupm and in the cells occupied by them in transformation from larve to adults. In perhaps the majority of species the transformation takes place at the end of the food burrow with or without a definite cell. In some ambrosia beetles the pupation takes place in the social galleries occuped by different stages of the brood, in others it is in the lateral larval cell, and in Stephanoderes the transformation takes place in closely joined





200 THE SCOLYTID BEETLES.

cells at or toward the inner end of the social gallery, the walls and partitions of these cells consistiiig of an ambrosia-like substance mixed with fine lborings.
F LIGHT HA BITS.

Further observations should be made on the flight habits of these beetles, but from whlat we~ kniow of a few species it would appear that in the samne, species flight may b~e either individual or collective. lit one( example notedl by the writer (Hopkins, 1899a, pp. 346"TS) a rge. imber of species, together with some of their associa tes, s(tienerand p)redlaceouis enemies, were found int one great, swNarmn. TIh(, p~eriod-; of flight vary wl11it the number of O-eierationjis ill a seaSo]1. Tlus species with a, single generationn have but one definite perTiod1 of flight, mhl hseiihnore flilone generation have two orniore p~eriod1s, or', wNhen the genertatiobus overlap, there may be a conlt in uous priod of flight t hir ilouot thle sealsonl.

SOCIAL HA BITS.

[Ii the social habits we-( finid some features of special interest, both in their relations to taxonomyi- an~d to parallel lines of modification. In the relation of thle sexNes there(1 is a wide range of variation from simple or un orgai zedl a] 1t intens ive p( lyga IiV to specialized or oro'an Lzed? lolyraunt, and1 a, gradual reduction in.i the p)rolportion of thle number of females,-, from I male and many females to 1 male and 2 females, and lbia ll 'N to specialized mA)Ioga ily.
in Ifqpoth enc m us, Step/ii Uodlres, A qiebor~us, and alliedl gemiiera the males are much smaller than the femafiles andl very rare. 'in certain species of A flieborus as many as 60) fema(,les to 1 male have been found inl one brood gallery, andl the proportion appears to be even renter in J1!pothettiu'm ats. Ini these groups., there is no system l i the relation of thme sexes or in eggsr-, of the broodl galleries of the females, and all live together- in the same galleries. Ini the other groups of genera of the subfaily ('m'>pialiuna' where there, is lio 4 ifference inl tihe size of the sex(-, tilei-M is, mohre evidlence of separate, egg gadlries for the difie-enit feles(- of thme social gr-otp, a1,,l thle ple-e er.1f( .1-,olll tief in ite Iam I ch aracteristic form'ms 01' l)I t tennis. lit~~Idi the lpdtll'tei(lelecv toada Sp ecialized] polvo'a milmols relat ion of the sex-es reflcht'5
it~higest e1t'lp~lle'Ilt in it fop1m(s, whlile ill ips8 there, is a tenl(leccV I )Wa I' I lm tals t0ilieFS o(f wvic icl i ie 11 ca5L'S ai'& liin iteo t,( 2 or :3 t( toIhe gaille'v In Co I m v lIiia' thle sexe(s ar mr eual dlix itIved, whle iii M 1rvpitirrin'o iP1muot ibima',t ainid I Ivesmina'11 there i, Cu teiilenev towvard 2 femflale's anld I maitle or to I odf eav, Thle last
I*- t4)P 'V IIII(I (r'TeaIt e t \ elit ill tiesll)" 1 aIIi ill, scolytriti lo't MI the( gi'ui 115 Sc()i/tils, 111,1.11 ill olther' silmih1 ies.






iPIEL1\T1NA1IY ('JAS811'ICATION OF SCOI.YTIAIDCA. 201

( k ILER~IE ES.

TIherie IS a widle variations il the t 'Vpes o r I( )'ls of the1 egg 4-11)(1 1 r( ( ( I galleries within the families, su1)fallillies, alld( tle ma1Jor 4,11(1 m1inor1 groups), andi ill sottle (~5' it lii the (reiiis. Each sp)(cis(r(1'I )o allied species of a genus or gr()l1l of alied gelera is ustiallY cliartict er1zC(1 i) someo- peculiar formt or fea ture ANh ich *11 ii)1 allY iv ases is :ifliceiit, in itself to in(1 icate the species, (refils, or groli])t It h it Ii )el(ns. therefore the galleries are of special taxoiiolllic, jitiport alic(' inl ili(1icating the natural position and rolupiluo, of ti( lie es aJl(I 2reiera.
It has 1)eell supposed that ta peculiar t :iN-e of' gallerY -was (hule to the character of the plant tissue lin which it W\NIs excavatedl or t hat it, hiad some relation to the species of plIant. It is foundd, however, tha-t the type of the gleyis the samite, 01r similar, for the samie spcties,1 regar(ss,- of the character of the sulbstacev 01r the species of p)lanit in which it is excavated. lin fact, the same species of spruce or pine. and the bark on the trunk or b~raniches, or the wood of thle sa-me11C pa-rt, of the tree, may have as many radlically different typ)es of ga,-llerie(> as there are different species of 1)eetles to make then.
It has also beent supposed that the type of a gallery was due to the peculiar structure of the beetles, such as the retuse or concave alid armedl elvtral dcl,,(ivitv in Ips, alsceniding<7 or exe\-avatc(1 abdominal sternites of Sco.Iqius, etc., but it is f oundA that certain species with the same or similar structures mnakev very (liff( xeii t typ~es of g'a lierie, while certain other species with verY (liflerentt structures make similar galleries.
The fact that there is (luite a (lefinlite relation b~etweeni the tyNpe of the gallery and the systematic. position of the species, genius., 'and group would indicate that the evolution of the g~allery has been from the simple to thle comiplex, anid that it has p)rogressedl with the evoluition of the beetles that make and~ inhabit it, li a soilewhat slimila-r manner to that of the (lominanit tenidency iti thc evolution of huinan (Iwelling places from the siniple cave to the miodlerni l)lacle. lIn other
w~~l.the simple and coiiplex-, galleries I'elreseilt ev 7olut ion witlm the maximumiii and minflulinl limits of ami inistinictive or dloinlanlt tendency coinmton to all of the individuals of the superfatilly ScolYtoidlea and are expre,-sed by each 'specie of a genus iii the varyin~g degrees of sdimplicity or perfection accortiig-( to the varying stge lin the evolution of the species.
The fact that the same or a similar-ty-pe of gallery is made by species of widely separately genera and subfamilies ilidicates thA we should not look for aln explanation of the origin and1 evolut ioni of types of galleries in the phylogenY of the species, but th-at a thorough consideration should be given to the explanation to be found iti paral-





202 THE SCOLYTID BEETLES.

lel evolution due to a common tendency which may lead to the same or similar results during the same or similar stage in the evolution of the species.
While the varying types of the egg and brood galleries furnish some very important taxonomic evidence, any attempt to classify the species of a family or subfamily according to such characters alone would give the same heterogeneous results as are found in the different classifications based on the elements of a single external or internal part or organ of the body. On the other hand, if the galleries of the species of the major and minor divisions of a subfamily are studied separately, it will be found that the character of the gallery and the species of the host tree will serve as most important guides to the natural position of a species or group of allied species.

TERMINOLOGY OF THE GALLERIES.
Following is a revised list with definitions of the terms used to designate the different elements of the scolytoid gallery.
Egg gallery.-The egg gallery is the burrow excavated by the parent beetles preliminary to depositing the eggs in niches along the sides or loosely in the gallery itself.
Social gallery.-The social gallery is one in which all stages of the broods from the eggs to the matured individuals and the parents live, as in Xyleborus, certain species of Platypus, Crossotarsus, etc.
Social chamber or brood chamber.-The social chamber, as in Xyleborus saxeseni, is a dilated portion of the tubelike gallery to accomodate all stages of the brood.
Death chamber (catacomb or garbage chamber).-The death chamber (Hubbard, 1897; also Hop)kins, 1898) is a section in the social chamber in which the dead individuals of the colony or the guests and enemies as well as other refuse matter are deposited and separated from the main chamber by a wall of the ambrosia fungus mixed with boring d(lust.
Entrance burrow.-The entrance burrow is made by one or the other sex as a preliminary to the excavation of the egg gallery, and may connect in a direct manner or laterally with the base of the gallery in the case of single galleries, or with the middle in the case of double galleries.
Nuptial (lateral or central) chaminber.-The nuptial chamber is excavated(l by one or the other sex (probably in most cases by the 1111male) at, i he base of the ent iance burrow and the mouth of a single or maIy, egg galleries. In Pityophthorus, Ips, etc., this chamber is short and broad, oblong, or rectangular. In some species of Scolytus, PhIt'oplthorus, Hylesi'nus, etc., the lateral entrance appears to serve tl he same 1)u)ose as the niul)tial chamber, while in Phlicosinus the chlaInl),r is at tihe bse of the egr galleries and entrance burrow and







extends to one or both sides. These chambers are usually oelpl-4d by the male of thie )polygamous colony or of the Ilmgaln)io uis pair.
Vent ilating burrow.-The ventilating burrow is the vert i'al burrow which is located at i more or less regular intervals in the roof of the egg gallery andm extends to ()or ear O le surface. It may serve 1 lhe purpose of ventilating the gallery, ()or, 1)erhlap)s more frequently, as a place for the storage of boring dust o(r an opening through which this dust may be ejected. Short burrows in t he roof or sides may be used as places in which the beetles turn around, or nmay serve the purpose of nuptial chambers.
Branching galler.-The branching gallery may branch from the central or nuptial chamber, or from the side of one of the main egg galleries. In the latter case it is referred to as a lateral branch.
Connecting galleries.-The connecting galleries are those of one or more colonies which are connected either through the central chamber or by lateral and primary galleries, as in many species of Pityogenes, Pityophthorus, Carphoborus, etc.
Terminal burrows. -The terminal burrows are excavated usually by the female beetle at the farther end of a primary or a lateral gallery, after the egg gallery is completed and while the brood is developing, as in Dendroctonusfrontalis (Part I, figs. 51 and 52).
Brood burrows.-The brood burrows are those excavated by the adults of a brood before the individuals emerge. They radiate from the respective pupal cells of the individuals, as in Dendroctonus, certain species of Ips, etc. In the case of species with a single generation annually, the developed brood may overwinter in the brood burrows.
Hibernating burrows. -The hibernating or overwintering burrows are those excavated in places other than that in which the broods developed, such as those of Ips, in the twigs and branches, or in the thick corky bark at the base of the trees, and those of Pdhloeophthorus, in the outer bark on the trunks of the living host trees.
Food burrows.-The food burrow is excavated by the adult in the same part of the tree in which it excavates its egg galleries, or in a different part, as in Scolytus rugulosus and S. quadrispinosus, which burrow in the living twigs at the base of a leaf stemin or bud, and in Phlocosinus, which burrows at the base of living twigs.
Trial burrows.-The trial burrows are those made by the parent beetles in the bark of living trees preliminary to the general attack and the excavation of successful egg galleries.
Abandoned or failure gallery.-The abandoned or failure gallery is one which, through the resistance exerted by the vital part of the plant attacked, the beetles are compelled to abandon or be drowned in the resin or sap.






204 THE SCOLYTID BEETLES.

Exit bu'rrow.-The exit burrow is that through which one or many individuals of a developed brood emerge. In the case of ambrosia beetles the entrance may also be utilized as an exit, but in the barkbeetles the exit is usually direct or indirect from the pupal chamber.
Larral mnine.-The larval mine is the food burrow excavated by the larve from the point where it hatches from the egg. The individual mine may be widely separated from or closely approximate to those of other individuals of the same brood, and they may be arranged in groups or those of the entire brood may be connected to form one common larval chamber.
Lamrval cell.-The larval cell is excavated by the larvae in the side of the gallery simply to accomodate the increasing size of the body, as in the case of many species of Corthyline where the food consists of ambrosial fungi provided by the parent.
Pupal cell.-The pupal cell is formed by the prepupal larva or by the pupa itself and is usually located at the end of the larval mine or food burrow of the larva. This is especially true in the case of the barkbeetles or the wood-mining larve, which latter, as in Micracis, Thysanoes, Scolytus nmuticus, etc., extend their burrows for a long distance from the bark mines into the wood. On the other hand, certain species of Dendroctonus form the pupal cell in the outer corky bark (D. frontalis) or in the social larval chamber (D. valens), instead of at the end of the larval mine as in D. ponderosa.
All of the named parts of the gallery have characters more or less peculiar to the species or group of allied species. Therefore the galleries as a whole, or in their- various elements individually, or in various combinations, are worthy of special attention in the search for taxonomic charact eristics.

('LASSIFI('ATION ()F THE GALLERIES.
LG (rAIEIF S.
In -an attemllpt to laissify thle scolytoid e(gog galleries it is imlportant, to remelmb)er that the newly excavated galleries in which the first sets of eggs are depositedd are more reliable in suggesting the type Or grou t e represelit tait 11-c the older ones, )ecailse ill SOnile species they may t)e so radically (lmitlged and c()Ifusedby secondary Ibrnlle s all1(t 1t e interilligliil) of two or more galleries that, I te cmnracterist ic type mlay be ob)scire(d.
LA L I 1 INES.

TIhe larval mies fiurliisli, 1to it liinited( extelit, eNvidce of proe(sslve 111o(0li ication, Is is fo llild ill elrdoctonl us. The larval 111111ines iii llost of tle ('0yiiali ll' ae WiO tit distinct ive characters, while ill Ilpilmi, llcviilialo t(i Scolytiitl tileir synilmetrial aillrallgeent






PREIMINAI!V CLASSIFICATION OF SCOIATIlI)E.\. 20)

represents a high stage o)f p)rogre( ss, aIndI consequent lv they are Ire( characterist ic of the species.
The forI.l of t egg (fler ao (v species insists of ()n11(, o(r 111oe
of three primary el1emeints ill Irelaltio lt 1 1 sU tl)sta1ce anil 11 fiber in which the gallery is made, as follo()ws: (1) Thile longit(udinal gallery,
(2) the transverse gallery, and (3) tie broad, irregular cliamiber.

TYPES ANDI) SUBTYPES ()F GG (1AI.I.Eils.

The various mod(lifications anld coibinat ion-) of the three primary elements seem to represent S general tI types ()r' groups, which are designated by numbers, and 32 more specific su)types ()or formlis, which are designated bv letters, as follows (see fig. 112): Group 1.-The simple or generalized type. (a) Simple, longitudinal; (b) simple, transverse; (c) simple cavities; (d) various combinations of a and b, with lateral branches.
Group 2.-The simple, irregular type branching from an irregular central or basal chamber. (a) Long, longitudinal, branching; (b) short, sublongitudinal, branching;
(c) short. transverse, branching; (d) various combinations of b and c. Group 3.-Ambrosia galleries. Division I, without lateral lareal chambers. (a) Simple, longitudinal, single or branching; (b) long, transverse, branching; (c) short,


7_ /
++[+dj dja jc a ++ d++ ,+ a++ i+

J/+ aJ++ <
1 2 3 4 5 6 7 8


FIG. 112.-Classification of galleries of Scolytoidea. (Original.)

transverse, branched, dilated. Division II, with lateral larval chambers. t d, Double, transverse, branching;
Group 4.-The specialized, intermediate, short type, blanching from a regular central nuptial chamber. (a) Simple to complex, transverse: b simple to complex, sublongitudinal: (c) intermediate combinations of a and b; (d, complex. symmetrical combinations of a and b.
Group 5.-The specialized, intermediate, long. longitudinal t lype, branching from a regular central chamber. (a) Simple. irregular types with few branches: (b specialized, many-branched types; (c) specialized, with few branches, usually three: (d) specialized, double, longitudinal.
Group 6.-The specialized, short, transverse type. a) Simple, irregular, single or double, transverse or subtransverse, and sometimes branching: (b) intermediate, regular, double, transverse or subtransverse; (c) specialized, regular. double or single. transverse. with or without lateral entrance chamber.
Group 7.-The specialized, short, double, longitudinal type. (a Irregular, branched ( Iicracis) type; (b) irregular, without branches, but with lateral entrance chambers; (c) intermediate, more specialized, with or without lateral entrance chambers; (d) highly specialized, without lateral entrance chambers.
Group 8.-The specialized long or short, single, longitudinal type. (a Long, irregular, winding, sometimes with lateral branches, with or without lateral entrance chambers at base; (b) short, irregular, without branches, but with lateral entrance
590260-15-----4







206 THE SCOLYTID BEETLES.

chambers at base; (c) regular, short or long, with lateral entrance chambers at base; d) the most highly specialized short or long type, without lateral entrance chambers at base.

The foregoing classification and terminology is based on the observed galleries of a large number of species representing 57 genera and includes the galleries of European species figured by other writers.

RELATION OF TYPES OF GALLERIES TO THE SUBFAMILIES AND FAMILIES.

The relation of the eight groups of galleries to the subfamilies is shown in the following table. In some cases one genus may be represented by several groups. In Pityophthorus 26 species are represented in groups 1, 4, and 5, and in Ips 39 species are represented in groups 2, 4, and 5.

TABLE VI.-Relation of groups of galleries to the subfamilies in the Scolytoidea.

Groups of gallery types and number of genera in each group. Subfamilies.
1 2 3 4 5 6 7 S

Ipida:
Division I- Genera. Genera. Genera. Genera. Genera. Genera. Genera. Genera.
Cryphalime.. 4 4 3--------ohina e ..... ...1 .... 53 2 .......... .......
orthylin -- .......... .. 5 .. ......... ......
Micracinae ---- ---------- ---------- ---------- ---------- 1 ..... 2 .....
Division IICrypturaina,. 2-----------------------------------------------------------1
Phleotribin .---------- ---------- ---------- 2 1 2 .......... 2
Hvlesininae. 2 2... ... ....-.. ..... ...-..... 8 2 7
Scolytid we:
ftexacolin ...... ..........- ......-...-...... -.. ------- 1..........................
13othrosternin m ..- .......... -......... -..... .... -....................-.... .....-1 .......Scolytinm----enin-" ........ ..........------ .......... ".....--- ...- 1
Scolytoplatypodidw:
Scolytoplatypodin -- ............ ....................- ............................ ....... .. .....
Platvpodida,:
i'latypodinw .....-..-.......-.----------2............. .......... ....................


This table shows that all of the simple types (1 and 2) are in the IpidT and that most of them fall in the first part of Division I, while the more specialized types fall in the last part of Divisions I and 1I, with the far greater number in the latter; also, that in ScolytidT specialized types only have been found. It is probable, however, that simple types will be found in the Scolytid when we know more
about the habits of the species of the other genera of this family. It is also interesting to note from Table VI the number of subfamilies and genera in which the same group types are paralleled.





I-RELIMINAR 'LASSI FCA!ION OF SC Y'IiJ '()I]) A. 207
TABLE VII.-Rlh(tio/ !grmup (4 guIllrixs t If]I flli(4 fi/I/Iyoi~.
.. .. .. . .. .. .. .. .. .... .. .... .. .. .. .. .. .. .. .. .... ... ................. .. ..... .. .
Ipi(1 .
Seool I T1
G ro uips. Seoly- l I dley
Division )ivision tPo1l \i(1 1o if.
1. I 1.

Genera. Gra. lra. G ii~ru. G(,nr!.
3....... 9 5 0 1
2 ... 4 3i 0 10 0
:3... 9 0 01)
4 ....... 3 2 0 0 0
5 ....... 4 1 1 00
6 ....... 2 8 1 0 0
7 ....... 3 2 2 0 0
08 1 0 0

In Hyipothenemus the types of galleries do not extend beyond group 1 and represent specific types a, b, c, and d; Cr!plbalus is also confined to the same group and types, while Pitqophthorws represents group 1, a and d; group 4, a, b, c, and d; and group 5, a and d. Ips represents group 2, a, b, c, and d, and group 5, a, b, c, and d.
The relation of types of galleries to species shows some striking examples of progressive modification within a genus and of parallel characters in different genera. It is not desirable to present a table to illustrate these relations in this connection, but it is intended to do so in subsequent parts dealing with the subfamilies.
While considerable attention has been given to the subject, a far more comprehensive study of the egg and brood galleries than has yet been made is required as a basis for correlating their taxonomic characters with the morphological characters of the species. TAXONOMIC RELATION BETWEEN THE BEETLES AND THEIR HOST PLANTS.
Among the scolytoid beetles there is often a close taxonomic relation between the species, genera, and groups of the beetles and the species, genera, or groups of plants they infest, so that we may often know the insect by the host, or the host by the insect.
In other words, the host, together with the character of the gallery of a beetle, will often not only serve to identify the species to which it belongs but will indicate its systematic position. In a like manner the presence of certain species of beetles will serve to identify the species of plant and indicate its systematic position.

PART OF PLANT SELECTED BY THE BEETLES.
The part of the plant in which the egg galleries are excavated is also of interest. In some species it is limited to the root or stem of an herbaceous plant; in others to the bark on the roots, main trunk, larger branches, and smaller branches, or to the twigs or fruit of a






208 THE SCOLYTID BEETLES.

shrub or tree. Indeed it is found that the species of an entire genus of beetles may confine their breeding places to a restricted part of the plants of a single genus or closely allied group. Therefore even the part of the plant infested by a species may be of considerable taxonomic importance in indicating the natural position of a species or genus of heretofore doubtful position.

CONDITION OF THE PLANT.

The condition of the plant or plant tissue at the time it is occupied by the beetles is of considerable systematic and economic importance. It ranges from young to old plants, living, declining, dying, and dead, and to different stages of decay of the plant or some part of its tissue. The fact that there is a relation between the species of beetles and one or more of the conditions mentioned shows that there is something of taxonomic value in this phase of the subject.

RELATION OF THE SPECIES OF BEETLES TO THE SYSTEMATIC POSITION OF THEIR HOST.
The primary and minor divisions and groups of plant species represented in which one or more species of beetles live range from the fruiting bodies of certain fungi of the Eumycetes to the higher flowering shrubs and trees of the Angiosperms, the greater number of species and genera being confined to the Pinaces of the Gymnosperms and the shrubs and trees of the Dicotyledonet of the Angiosperms.

RANGE OF HOST PLANTS.
The range of host plants in the families of the Scolytoidea may be designated as follows:
TABLE VIII. Range of host plants in the families of Scolytoidera.

Group of host plants.
Family in the Scolytoidea.
FuiieGymno- Monocoty- DicotyFungi. sperm ledoneas. ledonee.
-p d~ -------_ Rar .....C m m n
Ipid .. .. are...... Conuon.. Rare...... Common.
Solyitl None Hare.... None...... Do.
eolytoplatpo i ......... None .....P.. do....... Rare.
Platypoida ....... do ....... Coi nion. do....... Common.

Tle range of host )lants in tihe genera of true barkbeetles is usually 1ore re trilt e(d an(l characteristic 1iha in t he genera of ambrosia ho tles or in those species which live in d(lead(I or decaying bark or WOO(l.
Examples of restricted range of ho(st plants. In the C-ryphaline we find t hat ('rqphalo s is partial to Abies and Picea; Trypophloeus to





PRtEIMINAlN CL('A551 FICATION OF SC()J.YTOII)A. '0 A1Iiuts. a aid Poitulils. In i imPr~i Hie true J'fP* u n are lair0.,eN confinedI t(,- P'u us andI Pihu'a. Ili (-I -1lia the rillp. Gnath~otrich is is conlfitiedI to the I l (11,0111), wli 1 o'mal,1111h11i i partial to the dicotledlonous I rees,. I ii ( rvpt 11r',n d ie speciess (f
cr~ptwg1/. Jobirqwis, anid Th I(/m(tou us 1are C(oMtiled to Ph~ us '11)(I allied geniera. In Ilylesinintw Tniu l'I)piu) qiq 11)(1
JIlIlastes tire confined to Pituus, while- the true II'ilcSu 1* 11( ida
biuare part iculai'ly associal ed Ii fll~ u
Exam pics of wid( range o1 host plafdts. I ii ( 'rvplialim' II!/lpothf. th 1mus has a range of host plants from fungi up dhrotighi inay getlera oJ tew Mlono otvled(on ea and lDicotyledlonea' but is,, rarely found as) an iiiibitant of the Gymnospermte. X'i borasv, has the(, widest rtai, of alJ through the Coniferoe and AngTiospermte. IDr'ocets is divid''d between the conifers and allies of Qw' rcas. In (,'orthvylniie t ille e Xqloterus is divided between the G-m nos,-periraw anld a wide rng of the trees of the A ngiospermve. (lorth'~lis is confined to a, widle range of trees in the Angiospernmo, as is als-o Muwnrthiraml, ecp in the case of a few record-; from the Pin us aind .Jnitru.s group-. In Scolytinoe the genus Scolqjtas as at present recoglnizedl is divided between the genera of the Pinales (except Pin us and the Aiental. and Rosales. In Ilatypodinve there is a wide range of food plant- ~ in the trees of the Gymnosperie and Angiosperma..

ASSOCIATIONS OF SPECIES OF BEETLES A-ND SPECIES OF PLANTS.

In some of the genera which are restricted in the range of host plant,, as well. as in those with the widest range there are many species which are restricted to a single species or group of closely allied species of plants. In Phlcotribinoe there are species peculiar to iloriis, ~ls etc., and in Phloeosin us, with but very few exceptions, each seisis peculiar to, or prefers, a differentt species of cypress, cedar, or juniper. or group of allied species. In Sco/itas we find Hicoria, C/ni TUs I71/, Betula, &iltis, Quercus. Ab ies. Pict 0, P56 eydots aga tax/tfoijO. etc., with species of beetles peculiar to each plant grenus.

SUMMARY OF FAXo-Nomic EVIDENCE FURNISHiEl BY HOST REI.A'i'10 N S.

In a study of the relations between the insects, and their hostsomie rather striking facts have been determined which have furnished evidence to clear much of the confusion in clas~sificationi based on mnorphological characters alone and in which parallel or analogous characters have been mistaken for those of aftinity. By the old im-ethod ofmorphological distinction closely allidseisanVeeahv been widely separated in the classification and distantly related ones placed together. A number of such cases have been detected where the host plant and the character of the galleries- have been studied.





210 iTHE SCOLYTID BEETLES.
In other words, the physiological characteristics gave the best clue to the natural affinities of the various groups and led to the discovery of heretofore overlooked morphological characters which furnished conclusive evidence of their true position.
The close relationship between some of the existing representatives of ancient groups of plants and representatives of evidently ancient types of the beetles indicates that the beetles and plants may have been closely associated in their evolution from their respective primitive forms.
GEOGRAPHICAL DISTRIBUTION IN ITS BEARING ON TAXONOMY.
Superfamily SCOLYTOIDEA.
It is evident from our present knowledge that the superfamily Scolytoidea is represented to a greater or less extent in every section of the world where woody plants grow.
Family IPID1E.
The family Ipide is also represented by species in all of the great faunal regions. The subfamily Cryphaline, with its widely distributed Hypothenemus, Stephanoderes, and Xyleborus, has a wider range of distribution perhaps than is found in any of the other subfamilies. The Ipine are more restricted to the Holarctic regions and to the distribution of Pinus and its allies, Abies, Picea, Larix, etc. The Corthyline are more restricted to temperate, subtropical, and tropical America except in the genus Xyloterus, which extends through the Pahlarctic and Nearctic regions. The Micracine, with the exception of Liparthrum and Hypoborus, are largely restricted to north temperate America. In Crypturgine the genus Aphanarthrum is restricted to Madeira and the Canary and Cape Verde Islands, while Crypturgus has a wide range through the Palmarctic and Nearctic regions, and Dndroctonus, with one exception, is confined to North and Central America. The Phlceotribins and Hylesininm are widely distributed throughout the regions of tree growth.
Family S('OLYTID;E.
The family Scolytid, as represented by the genus Scolytus, extends over a wide range of the Palmarctic and Nearctic regions, but the greater number of genera and species are evidently to be found in the subtropical and tropical regions of Central and South America.

Family S('1OLYTO'PLATYPO DI D.E.
Tw family Scolytopilatypodid,a, so far as known, is restricted to s111all section)-s of the east eri Pahaictic an(I of the Ethiopian regions.





PRELIMINARY CLASSIFICATION OF SCOIYTOIDEA. 2l 1
Family PLATYP01)1 I)E.
The family Platyp)o(dida has a wide range tlhrouigll tI he tel)peral e, subtropical, and tropical regions of both continents.
There are many features in the distribution of genera and species which are of special interest, but there is need of information on many species from the different countries which at present are poorly orI not at all represented in collections.
PAIRED SPECIES.
The subject of so-called paired or parallel species is of special interest in connection with a study of the distribution. There are some striking examples of paired species in the genus Dendroctonus which, if they occupied the same local faunal area, would be (liflficult of separation on account of their close resemblance in structural characters. These paired species are brevicomis and barberi, frontalis and arizonicus, mexicanus and parallelocollis, monticolw and pondeross, piceaperda and engelmanni, punctatus and micans, and terebrans and valens. In each case the pairs are more or less widely separated from each other in their geographical distribution, as, for example, micans of northern. Europe and punctatus of the Appalachians of North America, frontalis of the Southern States and arizonicus of Arizona, barberi of Arizona and New Mexico and brevicomis of the Pacific Slope States, Idaho, Montana, and part of Wyoming, ponderosy of the central and southern Rocky Mountains and monticolx in the Northern Rocky Mountains and Pacific Slope.
There are any number of similar cases of so-called paired species in other genera, and the supposition that some of them are one and the same species has led to considerable confusion concerning the true range of a species. Between North America and Europe we have several examples, such as Anisandrus pyri of America and Anisandrus dispar of Europe, Dryoccetes autographs of Europe and Dryocoetes septentrionis of the western coast and Alaska of America, Xyloterus lineatus of Europe and Xyloterus bivittatus of America, Hylurgops glabratus of Europe and Hylurgops pinifex of America. There are many others common to two or more countries which superficially seem to be the same.
REVIEW OF TAXONOMIC CHARACTERS AND CHARACTERISTICS.
In a review of the foregoing discussion of the morphological characters to be found in the different stages of the scolytoid beetles and of the physiological characteristics in their habits, it is shown that there is a wide range of taxonomic elements by which to distinguish species and genera and to indicate or fix their position in the classification. Indeed the vast number of these characters and characteristics






212 THE SCOLYTID BEETLES.

and the wide range in their variation, together with the disturbing factors, or reversals, and parallel modifications, are enough to overwhelm, confuse, and discourage anyone who attempts to study and utilize them in a comprehensive classification. It is plain, however, that it is only through such a comprehensive treatment that we can hope to approach the ideal natural classification.
MORPHOLOGICAL CHARACTERS.

In a review of the morp)hological characters it is found that the tarsus and tibia are of special value in the classification of the superfamily; the head, pronotumin, elytra, and third joint of the tarsus for the family; the head, tarsi, pronotum, elytra, anterior coxe, abdominal sternite, and pygidium for the subfamily: the antenna, eyes, pronotum, elytra, tarsi, tibie, body, abdominal sternites, anterior coxe, and mouthparts for the genus, and for the species there is such a wide range of characters of varying, and sometimes reverse, value in different genera that they can not be specified except for limited groups. IHowever, the size, form, color, vestiture, and sculpture of the body, the front of the head, elytral declivity, etc., are in general among the most important bearers of specific characters.
In the digestive system the masticatory plates of the proventriculus appear to be of special taxonomic value when applied to subfamilies, genera, and species.
In the reproductive organs of the male there is a very wide range of variation in the primary and secondary elements of the posterior or chitinized section, but with a few exceptions their taxonomic value appears to be restricted to major and minor divisions of the genus and especially to the separation of the species. In the anterior section of the organs the length of the ductus ejaculatorius and the form of the testes, seminal vesicles, vas deferens, and mucus glands appear to represent the principal taxonomic elements, and they are of varying value as applied to major and minor groups.
The female reproductive organs, like the proventriculus, appear to possess a number of taxonomic characters of family, subfamily, and generic value, such as t he presence or absence of the cement glands and t heir varying characters and ti presence andI character of the sperilathlleca wit i its seminal 11duct.
In th le seo iary sexual characters we filndI a few wllich are peculiar to a genus or to gro()ups of allied genera, but in general their pricipal value appears to )ie in (listinguislling the species.
In thie p)p), it is found that the head and the tergal, lateral, pleural, caudal, anlld femnoral spines appear to() be the most important taxoIMl niC eleielits.
In t 1le larva' there is a wide range f variation in the form of the b)(dy and inl some of the primary elements of the head and posterior






PtRELIMINARtY ( LASSI FICATION (OF S(Cl I ()IDEA. 213

abdominal segments, sp)iracles, (tc., whichJ are ()of value in starting the families, but the majority ( Of thesc liracters tre tf great es valie in connection with the genera and species.
The e,,, andt embryo (lt u|tless be(;ir si() mp)tntc mmes
T r7 10OgAl H fOdl 1OHOH important ll ra er44008
but they have not been sufliciently stud(ied by the writer to justify their (discussion inii this connection.

PHIY IOlA)(,IAL 1AtIIAITA( l lIt.
A review of the evi(lence relating t() the p)hNi:i)l)gieIal cllaracteristics shows that the feeding, bredining, fliigh t, afl( i sial hlabitis, t lie galleries, larval mines, host plants, the species ()f plat, lthe p)art ()of the plant occupied, conditions of the plant, restriete(I (or wide ranllge of host relations, and features in geographical distribution have something to contribute in facts and evidence of more or less taxonomic importance.

CORRELATION OF MORPHOLOGIC(AL AND PHYSIOLIO(iI CA ELEMENTS.

In order to arrive at satisfactory conclusions in regar(l to the proper correlation of the mass of taxonomic data mentioned in. the foregoing review one must have a far more comprehensive and first-hand knowledge of the subject as applied to the species of the world than is possessed by any investigator at the present time. Therefore it is the object of the writer to call attention to the need of further investigation of this broader principle of zoological taxonomy rather than to attempt to draw conclusions. It is evident, however, that at some future time the essential facts will be correlated into a system which will not only indicate true natural relations but perhaps give a better clue to the action of natural laws and a better interpretation of the fundamental principles involved in the evolution of life in general.
In order to arrive at sound conclusions the whole subject must be investigated without prejudice for or against any theory as to phylogenetic origin of the organism, or as to the primitive or recent charactor of an organ or element. The problem must be attacked with the view of locating the more important or essential facts relating to the distinguishing characters and characteristics as applied to the species and their various aggregations into genera, subfamnilies, and families and the major and minor divisions of each. In other words, a given group of organisms should be studied in all of its morphological and physiological aspects with the view of locating, by the process of elimination, the elements of primary importance until one or more characters in each of the principal morphological and physiological groups of taxonomic elements are found to correlate in the formation of a harmonious taxonomic compound.
It has been shown in the foregoing pages that, a classification based on any limited set of external or internal elements of the adult body,






214 THE SCOLYTID BEETLES.

such as those found in the proventriculus or in the male or female organs, will suggest a phylogenetic system, but when it is found that each system differs from the other to such an extent that the same genus or species will occupy a radically different position in the different systems it is perfectly plain that the true taxonomic value of the elements has not been correctly interpreted or applied. On the other hand, it is equally plain that if characters can be found in all or a majority of the groups of external and internal elements which point in the same direction, we may safely assume that we have more nearly approached the true principle involved and the ideal classification.
Examples of an attempt by the writer to correlate and harmonize the various morphological and physiological elements will be found ili the synoptic tables of Dendroctonus, Part I of this bulletin, and of Pissodes in Technical Series 20, Part I.
PARALLEL MODIFICATIONS.

Parallel modification in morphological and physiological elements is without doubt an important factor to be considered in taxonomy. It is evident from a comparative study of the various systems of classification that the failure of taxonomists fully to realize its importance has in many cases led to wrong conclusions. It has been shown in the foregoing discussion that there are a great many examples of parallel characters and characteristics in widely separated species and genera and that if they are not recognized and properly interpreted as such by the taxonomist, radically wrong positions will be assigned to many species and genera.

REVERSALS.
The reversal of characters and characteristics in different species of the same genus or in different genera and larger groups is another important fact to be kept in mind, especially as related to secondary sexual characters. Therefore it is never safe to conclude that because a given character or a group of characters is of special value in (istinguisiing one group, genus, species, or sex, it will hold in all cZases. There have been numerous examples of wrong determination of the sexes from a failure to recognize this principle, as has been pointed out by the writer (Ilopkins, 1894, pp. 274-280) and Blandford (1895, pp. 83-86). As has been shown on preceding pages, reversals are also found in specific, generic, and group characters, eveil to the sub(ivision of the superfamily, where we find a most st rising exanl le in t he reversal of the apical spine or process of the anterior tibia from t he imner to the outer angle.






PRELIMINARY CLASSIFICATION OF SCOLYTOIEA. 215

PROGRESSIVE MOD)IFICATIONS.

The discontinuous yet more or less progressive challge o()r variation in the modification of morphological and physiological eleinients along definite lines within the minor to majo()r groups is very evident in every group. The more this subject is studied the more we are convinced that there are certain import alt facts involved in this principle that have not been satisfactorily (xp lained )y any theory of the processes of evolution, The recognit i) ai(nd application in taxonomy of those unexplained features does not, however, necessarily require the acceptance or rejection of any theory o()f orthogenesis or phylogenesis. It is only necessary to correlate them with other more easily explained elements of distinction or to utilize them as guides to the position a species or group should occupy in a given series.
EXAMPLES OF PROGRESSIVE MODIFICATION.

The examples of progressive modification in morphological characters and physiological characteristics which have been noted by the writer in the scolytoid beetles may be summarized as follows:

Morphological characters.
Body small to large.
Body slender to stout.
Body with scales to hairs, to glabrous. Head concealed to exposed.
Head short and broad to narrow and subrostrate. Head with front convex, glabrous, to concave and pubescent or fringed. Head with eyes oblong, elliptical and not emarginate,. to short, oval, and deeply emarginate or divided.
Antennal joints of funicle increasing in number to the limit of seven. Antennal joints of club decreasing in number through fusion or disappearance of sutures.
Prothorax long and narrow to short and broad. Prothorax with sides not margined to margined, or not enmarginate to emnarginate. Prothoracic pleurum convex to flat and concave. Tarsi with third joint simple to emarginate and bilobed. Tarsi with first joint short to long.
Elytral declivity convex and smooth to rugose and armed; retuse to concave, with the margin unarmed to strongly armed. Sexes of unequal size and the males rare to equal size and the males common. Secondary sexual characters obscure to prominent.

Galleries.
Simple cavities in decaying bark and wood, to complex designs and regular forms of egg galleries and larval mines.
Excavated in bark to excavated in wood, seeds, etc.
Social habits.
Unorganized polygamy to organized polygamy, to highly organized monogamy.
Independent larvee, procuring their own food. to dependent larve, with the food provided by the maternal parent.






216 THE SCOLYTID BEETLES.
STATISTICAL TAXONOMY.
The subject of statistical taxonomy has received considerable attention by the writer and an attempt has been made (Hopkins, 1 911, pp. 28-30, P1. II) to show its successful application in the genus Pissodes. The detail and accuracy required for this method and the difficulty of determining a specific and taxonomic formula are so great, however, as to be rather trying on the patience of the investigator. Therefore it is the opinion of the writer that it should not be resorted to except in cases in which other methods fail to give satisfactory results and then only when the elements to be included are of such a nature as to be readily available for the mathematical determination of relative proportions. There is in this, as in many subjects relating to taxonomy, a need of a more comprehensive investigation in order that the most reliable basis for conclusions may be reached.

THE SPECIES.
Reference has been made (Part I, p. 66) to the writer's views on specific distinction and the range and limits of specific variation. In addition it may be said that no species can be established beyond dispute without a knowledge of both the morphological and physiological elements of distinction. This does not, however, preclude the recognition and naming of imperfectly defined and poorly represented species and of retaining them as long as they can be readily distinguished from other allied forms. Such names and definitions serve as a basis for study until it is more definitely shown whether or not the forms are worthy of permanent specific distinction. There is necessarily a. wide range in the relative prominence of the distinguishing characters as between a species which is the only representative of a genus and subfaminily and one of a group of closely allied species. It is found, however, that for the purpose of systematic and economic investigation the isolated species may be of no more value for study and may contribute no more to the advancement of knowledge than the one which is with difliculty separated from its congeners.
Since we now sistupon a single specimen as the author's desicnation of the type of a described species it is (deemed byio the writer to be perfectt ly proper to base the description of a new species on a single s)ecimlen, provided tihe author of the description is sufficiently familiar witb the l)reviolslXv described allied species amld genera to enable him to rIecogniize the characters an characteristics which are of real specific ii portance.
VARIETIES, RACES, ETC.
rhlr0e 1 in all sci a greater or lesser angl O of Variation from the t1 pe, ald1 often somle groups of Ind(iviluals may be so differentt as to il(icate a distinct vaiiet y or race. If such variant forms are





PRELIMINARY CLASSIFICATION OF SCOI.YTOIDEA. 217

found intermingled with the brood s of tile t pical trms and, tlhe characters are not stlflicientlyv (constant to distingiuish tlhemn as sep arat e species they should simple be considered as conilg witi.in i.e ran~e of specific variation, but in the writer's opinion these varieties should not be distinguished by a trimonoiul.
In some ge"nera and species the sexes nuy so differ in whole groups of characters as to indicate, in some cases, different genlera. ut there is always some character or set of characi ers coinunaon to )both sexes which would point to the same species even if they were not found associated in the same brood.
There is evidence that in some of the species of Xy/Uborus and allied genera in the Cryphalinas there may be occasional individuals which represent a degenerate form or a caste in the social relations of a brood or colony, with uniform but radically different characters from those of either sex, and that on account of the radical differences which separate them from the species with which they have been found they have heretofore been recognized as good species. Xyleborus planicollis Zimm. may be such an odd member of the Xyleborus inernmis colony and Xyleborus viduus Eichh. an odd type of the Xyleborus fuscatus colony, but further observations will be needed to settle the question. If this should be true in these cases it may hold with isolated cases in other social species, like those of fHypothenemus, Stephanoderes, Dryocates, etc.
THE GENUS.

There is more latitude, perhaps, for the selection of distinguishing characters of the genera than there is for the species, but the same principle applies. There must be some single character or group of characters common to a group of allied species which will serve to distinguish the group readily from all other allied groups. The range of departure or variation from the type of the genus is restricted in some genera, but in other genera with many species there may be a very wide range, so that the species will fall in distinct divisions and subdivisions, which are designated by some authors as subgenera.
Unfortunately there is a wide range in the opinions of different authors as to the limits of a genus. Some go to the extreme in restricting it to closely allied species while others go to the opposite extreme (Hagedorn, 1910) and include a large number of genera or so-called subgenera. It is plain to the writer that of the two extremes the latter is the more objectionable because it will certainly contribute more than the former toward retarding than advancing knowledge. The writer believes that there is a middle ground on which systematists should endeavor to get together in order that there may be more uniformity in the conception and definition of the genus.





218 THE SCOLYTID BEETLES.

NOMENCLATURE.
Nomenclature, as applied to taxonomy, is a subject on which there are wide differences of opinion, and it is evident that until there is more uniformity there will be continued contributions to the confusion of knowledge along with those which contribute to its advancement.
It seems to the writer that the subject of designating by name varieties, forms, races, subspecies, and subgenera should demand the special attention of systematists with the view of coming to an understanding as to the limiting of such names to the more definite concepts, as those of the species or genus. It would seem that if we should limit the names to the species, genera, subfamilies, families, and superfamilies within an order and designate the major and minor divisions of each as divisions (T, II), subdivisions (A, B, C, D), sections (al, a2, etc.), subsections (bl, b2, etc.), series (cl, c2, etc.), and subseries (el, e2, etc.), it would be in the line of progress toward a consistent, practical, and uniform method of expressing the varying ranks as interpreted by different authors. It would avoid, at the same time, the use of names for divisions and subdivisions which have different meanings in the systems proposed by different authors and prevent the accumulation of obsolete names with every change or important advance in the classification.
In the systematic treatment of the scolytoid beetles the writer fails to see the need of recognizing subspecies or subgenera. The species and the genus are the two most important biological concepts on which to base both systematic and economic investigations. They serve, also, as the most important units on which to base a classification. Therefore the writer holds that the individual represents a species and that a species represents a genus; hence the introduction of the trinomial for a subspecies and the naming of a subgenus are unnecessary. Moreover, he believes that a general practice of giving names to such divisions of these taxonomic units will ultimately lead to endless confusion and retard rather than advance the spirit of research and the acquisition of knowledge. At best the designation of the species and the genus to which a given individual should be referred is an arbitrary interpretation of a concept. Therefore, when an author designates an individual or a group of individuals as representing a subspecies, or a group of species as representing a subgenus, it involves the assumption that the concept is a fact and that he has sufficient knowledge of this fact to enable him to analyze it into component categories the relations of which are so definitely determined as to justify the subordination of one part to another.
There is such a wide range for the interpretation of specific and generic distinctions and such a vast difference in the relative rank of such (istinct ionis, between isolated survivors of highly specialized and





PRELIMINARY CLASSIFICATION OF SCOLYTOIDIAE1. 219

ancient groups and coninion, closely allied, an(i varial)l('e forms, that the difference between two species inl one genus may b(e equivalent to or greater than that between two allied( genera. In a like manner the difference between two (renera may be Almost equivalent in rank to that between two allied subfamilies. Therefore the fact that a given groupof individuals or agroup of species appetrs to represent a position of lower rank than that of an allied species o()r genus is not sufficient reason that it should be designated as a subspecies ()or subgenus. In other words, it is the writer's opinion that if a group of individuals is sufficiently distinct from allied groups to justify its designation by a name, it should be recognized as aspecies; and if, on the other hand, the group is connected with allied forms by such a number of intermediate forms as to render its specific distinction doubtful, it should be included with other variable types under a species name, and that the same principle should hold in regard to the genus.
All of the purposes served by the subspecific designation can be served just as well, if not better, by classifying the individuals of a species into major and minor divisions, sections, etc., and letting these represent the same conception as that represented by the named subspecies, and on the same principle the divisions and subdivisions of a genus will serve the same purpose as if designated by names.

TYPES OF GENERA.

Difference of opinion among systematists who have worked on the scolytoid beetles, guided as they have been by different rules and conceptions as to what constitutes a valid genus, has led to much uncertainty and confusion as to some of the older names for the genera of our common species. Therefore it seems necessary that the author should present the evidence which appears to him to be conclusive in regard to the generic names and the synonymy of Scolytus, lps, Tomicus, Cryphalus, Hypothenemus, etc.
Genus SCOLYTUS Geoffroy.
It has seemed to the writer that there is not sufficient reason or authority for the suppression of the name Scolytus as proposed and clearly defined by Geoffroy (1762, p. 309). The single "species" of the "genus" recognized by him was at the same time (p. 310) indicated by a number, the genus name (Scolytus), and a reference to a figure (Vol. I, pl. 5, fig. 5), and the characters were more clearly defined in a description.
Miller (1764, p. xiv) recognized the genus Scolytus Geoff. and referred to the original description and figures.
Schaeffer (1766, Tab. CXII, figs. 1, 2, 3, 4) redescribed the genus Scolytus and described and figured the species indicated by Geoffroy, but did not name it.





220 THE SCOLYTID BEETLES.

Linmus (1767) failed to mention the genus or to refer to Geoffroy, Miller, or Schaeffer.
Fabricius (1775, p. 59) recognized the species described by Geoffroy and redescribed it under the name Bostrichus scolytus, with the citation "Geoff. Ins. 1-310, [No.] 1, Tab. 5, fig. 5, Mal." Thus Fabricius recognized the species indicated by Geoffroy on page 310, but did not refer it to the genus described on page 309 under the name Scolytus because he (Fabricius) evidently considered it synonymous with Bostrich us. Consequently, the name proposed by Geoffroy for the genus should stand with Bostrichus scolytus (Fab.) as the type.
Sulzer (1776, Th. 1, p. 21; Th. II, Tab. II, f. 13k), under the name Dermestes scolytus, described and figured the species indicated by Schaeffer, 1766.
Miller (1776, p. 57) published a description under the name Scolytus punctatus but referred it doubtfully to Geoffroy's figures.
Goeze (1777, p. 143), under the name "Dermestes scolytus Geoffroi," cited Bostrichus scolytus Fab. (1775), Scolytus Geoff. (1762), and Scolytus punctatus Mifll. (1776). Goeze evidently did not mention "Geoffroi" as a specific name but merely to indicate that Geoffroy was the author of or authority for the name Scolytus.
Linnaus (1788, 1793, p. 1602) recognized Bostrichus scolytus Fab. and cited Fabricius, 1787, Geoffroy, 1762, Sulzer, 1776, and Schaeffer, 1766.
Ilerbst (1793, p. 124) described the genus Eccoptogaster with Bostrichus scolytus Fab. as the type.
Olivier (1795, No. 78, p. 5, Pl. I, fig. 4 a, b, c) adopted the name Scolytus for the genus and cited Geoffroy, 1762, and Fabricius, 1775, but substituted for the species the name destructor in the place of Scolytus Fab., evidently concluding, as other contemporary writers did, that the generic and specific names could not be the same. In fact this opinion evidently influenced the action of Fabricius, MiUller, Ilerbst, and others.
Curtis (1824, p. 43) designated the type of the genus Scolytus as Bostrichus scolytus Fab.
Genus IPS De Geer.
There .ppears to be no room for doubt that the genus Ips of De Gjeer (1775, p). 190), with Dermestes typographus Linn., 1758, as the type, has priority over Ips of Fabricius (1776, p. 23).
Genus TOMICUS Latreille.
Lutreille (1802, p. 203) diescrib(d the genus Tomicus with Hyles'inus piniperda Fab. (1801, p. 392) as the type, but H. piniperda of Fabricius is, as cited by him (1801, p. 392), the same as Bostrichus piniverda (L.) Fab. (1775, p. 60; 1792, p. 367) and Dermestes pinsi-





PRELIMINARY CIAS81I'CAT1UON OF~ SCOLYTOIDEA. 22 1

perda Linn. (175S, p. 355 (a11( 1767, p. 563.) F11(iviefofl' it tiper that the name Thrn'wus should stand, with IHyesinklH pin'iperda (L.) Fab. as the type. Thie slight (lifferelice in the (iescrJJtion hy Fa bricius of the insect he idientifiedl as Lintiveus's species doe s tot, warrant the conclusion that it was (lilferentt, because the species has the characters mentioned.
Thespeiespiniperda L.
piniperda IL., 1)erinestes Liiin OeS, 1758, p. 355; 1761, 1). 1 1"); I 767, p. 363. piniperda L., Bostrichits Fabricius, 1775, 1). 60; 1792, p. 367. piniperda L., Ifylesinus F'abricius, 1801, p. 392. piniperda L., Tornicus Latreillc, 1802, p. 203. (Type)( ofgmi. piniperda L., Blastophagus Eichhoff, 1864, p. 25. (Type of germ.".) piniperda IL., Myelopiluis Eichhoff, 1~878, p). 400. (Type of genus.) Genus HYLASTES Erichson.

Erichson (1836, p. 48) described the genus IHylastt's to include Bostrichus ater Pavkull, Bostrichus angustatus Herbst, etc., stating that Bostriclius ater Fab. was not a~ scolvtid. Therefore, since Bostrichmus ater Paykull is a good species, it stands as the type of the genus Hylastes Erichson, as designated by Thomson, 1859, p). 146.
Genus CRYPHALUS Erichson.

Erichson (1836, p. 61) described the genis (irypiwius to include A pate tiliw Panz., A pate fagi Fab., and Bostriclois asperatus Gxyil. Thomson (1859, p. 146) designated (Bostrichws) Urylphalus asperatus Gyll. as the type and (p. 147) referred Cry piwlus tilix Panz. to his monob asic s ubgen us Ermoporas and (1865, p). 360) Cryphams fiagi Fab. to Ernoporus.
Hypothenemus Westw., 1834, p. 34; E1rnoporus Thorn., 1859, p. 147; Trypophloxus Fairm., 1868, p). 105; Stephanwdercs Eichih., 1871, p). 132, and &iyphaloides Form., 1908, p). 91, are all sufficiently distinct from (Cryphalus Erich. and from one another to stand as separate and distinct gen~era; therefore they should not, in the op~inioin of the writer, be considered as subgenera of Ur'yphaius.
Genus HYPOTHENEMUTS Westwood.

Westwood (1834, pp. 34, 36, P1. V1I, fig. I a to h1) dlescribed1 the genus Hylpothenemus with erudiums Westw. as the only spcies andl mentioned and1 illustrated a three-jointed funiicle of the antenna as one of the distinguishing characters.
Duvall (1868, p. 105, 1)1. 33, fig. 161) examined specimens from the type series and redescribed and figured the species, and referred to the funicle as having but three joints.
Eichhoff (1879, p. 165) referred the genus Hypotheiterins Westw., and species eruditus Westw. to synonymy under Stephanoderes
59026-15-5





222 THE SCOLYTID BEETLES.

aricex (Hornung, 1842, p. 117 [not 115]) because he found that certain species previously referred to Hypothenemus had five joints in the funicle of the antenna instead of three, as designated by Westwood.
Fauvel (1884, p. 315) examined specimens of H. eruditus Westw. from the type series and compared them with examples of Bostrichmu boieldieui Perroud, 1864, p. 188, and B. aricca Hornung, 1842, p. 117, identified by Eichhoff, and concluded that all three were identical, and that Ilomeocryphalus Lind., 1876, p. 168, as represented by Stephanoderes ehlersi Eichh., was identical with Hypothenemus Westw.
Newberry (1910, p. 83) determined that the funicle had four joints.
Through the kindness of Prof. Poulton, the writer had the opportunity of examining a specimen of H. eruditus Westw. from the type series, and the funicle was found to be four-jointed. It is not improbable, however, that the antenna examined by Westwood was from a male, which, in this genus, is smaller than the female and has but three joints in the funicle. Therefore there can be no doubt as to the validity of the genus Ilypothenemus Westw. as distinguished from the genus Steplanoderes Eichh., which has a five-jointed funicle.
Genus POLYGRAPHUS Erichson.
Erichson (1836, p. 57-58) described the genus Polygraphus, citing Dermestes polygraphus L. (1758, p. 355) as synonymous with P. pubescens Fab. (1792, p. 368); but since P. polygraphs L. has priority, the genus stands with Dermestes polygraphus L. as the type.
Genus LEPISOMUS Kirby.
Kirby (1837, p). 193) described Lepisomus as a subgenus of Apate Fab., including three species, one of which, Apate (Lepisomus) wnigriceps, has been referred to synonymy (Lec., 1868, p. 169) while Apate (Lepisomuis) brevicornis is not recognizable, probably a synonym. Therefore Apate (Lepisomus) rufpennis Kirby is the type of the genus Lepisomus, which, on account of the six-jointed funicle, is a go()od genus. For the same reason Polygraplhus grandiclava Thorn. (1886, p. 62) must also be referred to this genus.

DESCRIPTION OF A NEW GENUS AND SPECIES.
WEBBIA n. gen.a
Antennal funicle four-jointed, the fourth broad; club narrowed from middle to base, broader than long, with one sinuate chitinous sutilre on the obliquely truncate anterior face, the posterior face
'a This genus and spv1o 'isis described here in order that the subfamily may be inclucIded in the chsifintaion.






PHEI MINAH V CLASSIFICATION OF SCO )TOIDEA. 223

without sutures: eyes oblong, ellil)tical, deeply eimarginate; anterior tibia strongly narrowed to apex, with submarginate row of closely placed teeth on the ventral side; elytral declivity with many closely placed marginal teeth; lateral margin of l)ronlotum acute, a ni(teior margin without serrations. Type of genus, Vebbia d ipterocari new species.
This genus is named for Mr. J. L. Webb on account of the large number of scolytoid beetles collected by him (during his brief employment in the Philippine service.
Webbia dipterocarpi n. sp.

Length, female type, 3.1 mm. Subelongate; pronotum and all
but the declivity of the elytra light ferrugino us, the declivity black. Pronotum with anterior area swollen, opaque, nearly smooth: apex steep, subtruncate, and finely rugose; me(lian an(d posterior areas smooth, subopaque, and very finely punctured. Front mod erately
narrow, subconvex, opaque, with fine median line. Elytra to near declivity smooth, shining, with fine, closely placed, and confused punctures with no trace of striT, narrow, and near vertex slightly swollen, densely opaque, nearly black; decli'ity steell, flat, opaque; interspace 1 elevated, smooth; interspaces 2 and 3 each with straight rows of granules: margin from vertex to apex arme't each side with 10 closely placed serrations or teeth, becoming slightly larger toward apex. These teeth evidentlv represent the 10 interspaces of the normal elytra. Near Pagbilao, Philippine Islands, in wood of (lead log of Dipterocarpus graditflorus Blco., August 7, 1903. J. L. Webb, collector. Under his number 94c.
Type.-Cat. No. 7406, U. S. National Museum.
Length, male type, 2.6 mm. Subelongate; pronotutim slightly broader than elytra which are narrowed toward declivity, light ferruginous throughout. Head narrow, shining, with deep epistomal impression and a slight posterior impression. Pronotum opaque, finely rugose throughout, with distinct median impressed shining line to anterior declivity which is steep) and strongly retuse to anterior margin, sides slightly narrowed from anterior angles to base, lateral margins subobtuse; elytra with sides slightly narrowed toward declivity, shining, punctured as in female but with stria evident and faintly impressed; declivity steep, flat, opaque, rugose, but without elevated interspaces, margin with but seven marginal teeth, coarser toward vertex and arranged in groups of 3-2-2. In a lateral aspect the dorsal line forms a broad curve from the mandibles to the apex of the abdomen. From same colony as the female.
The smaller size and general appearance of the male suggests affinities with the Xyleborus group but it is radically different in all of the more important characters.






224 THE SCOLYTID BEETLES.

The fact that specimens were collected in the wood indicates that the food habits are similar to those of Crossotarsus lecontei, found in the same log.
The pupa is peculiar in the absence of caudal spines, the presence of tergal and pleural hairs instead of tubercles, and the length of the wing-pads, which extend to the apex of the abdomen.
The larva, as shown by a dried specimen, appears to have the posterior part of the body stouter, then narrowed toward the apex of the abdomen.

PRELIMINARY CLASSIFICATION OF THE SUPERFAMILY
SCOLYTOIDEA.
KEY TO THE FAMILIES.

(See P1. IX.)
I. Anterior tarsi with joint 1 shorter than 2, 3, and 4 together.
A. Anterior tibia without prominent process on the outer apical angle.
Family Ipide.
B. Anterior tibia with prominent process on the outer apical angle.
al. Anterior tibia without prominent rugosities on ventral area.
Family Scolytide.
a2. Anterior tibia with prominent rugosities on ventral area.
Family Scolytoplatypodide.
II. Anterior tarsi with joint 1 longer than 2, 3, and 4 together.
C. Anterior tibia with prominent apical process and with rugosities on the
ventral area....................................Family Platypodide.

Family IPID2E.
KEY TO THE SUBFAMILIES.
(See Pls. X, XI, XIII, XIV.)
I. Pronotum with anterior dorsal area commonly rugose; head concealed from above; anterior tarsi with joint 3 simple.
A. Abdominal sternites 5-7 not strongly ascending.
al. Anterior tibia broader toward apex or serrate on outer margin.
1l. Abdominal sternite 7 with posterior margin always rounded.
1. Subfamily Cryphaline.
b2. Abdominal sternite 7 with posterior margin rarely rounded.
lc. Pronotum and elytra clothed with scales or hairs, very rarely glabrous ................................ 2. Subfamily Ipine.
c2. Pronotumin and elytra without scales, commonly glabrous or sparsely pubescent.................3. Subfamily Corthylinl.
a2. Anterior tibia not d(listinctly broa(lder toward apex or not serrate on
outer margin.
b3. Anterior tibia not strongly narrowed toward apex, apical tooth
stout; antennal club compressed; elytra with scales.
4. Subfamily Micracine.
b4. Anterior tibia strongly narrowed toward apex, apical tooth small;
antennal club thickened at base, with anterior face obliquely truncate; elyira with hairs...................5. Subfamily Webbine.
1. Abdominal sternites 5l 7 strongly ascending; tibia broadly compressed, outer
margin (rrate ................................ 6. Subfamily Xyloctoninue.






PlREILIMINAlRV CL.ASSIFICA'I'ON OF SCOi' OID1EA. 225

II. Pronotum with anterior dorsal area connionly smooth; hea(d exposed or rarely
concealed from above; tarsi with joint 3 simple or bilobed.
C. Antennal c(li) sul)glo()bose, ompressed to lamiite, never (o ial.
a3. Body slender to moderately stout; prootur longer than broad or not
broader than long...........................7. Subfamily (C'rypturgi nwe.
a4. Body stout; plronotun always broader than long.
8. Subfamily Phla otribine. D. Antennal club usually coijeal, rarely couipre1ssed ..9. Subi)family I ylesininm.
10. Subfamily Phh oborinme. Family SCOLYTIDE.

KEY T(O) THE SUBx3FAMIES.

(See Ps. XI, XV, XVI.)

I. Pronotum constricted toward the middle; anterior tarsi with joint 3 simple.
11. Subfamily C(optonotina. II. Pronotum not constricted toward the middle; anterior tarsi with joint 3: simple or
bilobed.
A. Anterior tibia with small tooth on inner apical angle extending beyond the
tarsal insertion; tibia with at least one tooth on the outer margin, in addition
to the alical one.
al. Eyes not divided; tibia with outer margin armed.
bl. Pronotum with transverse rugosities on anterior area.
12. Subfamily Hexacolinue. b2. Pronotum without transverse rugosities on anterior area.
13. Subfamily Bothrosternine. a2. Eyes divided; tibia with outer margin unarmed, a
14. Subfamily Hyorrhynchine. B. Anterior tibia with small tooth on inner apical angle not extending beyond the
tarsal insertion.
a3. Abdominal sternum convex throughout; antennal scape not very short 15. Subfamily Camptocerine. a4. Abdominal sternum not convex throughout; antennal scape very short.
16. Subfamily Scolytinve.

Family SCOLYTOPLATYPODIDE.

(See Pls. XII, XVI.)
Anterior tibia with prominent lateral process at outer angle; third tarsal joint simple ...................................... 17. Subfamily Scolytoplatypodinaa.

Family PLATYPODIDE.

KEY TO THE SUBFAMILIES.

(See Pls. XII, XVI.)
I. Third tarsal joint simple.......................... 18. Subfamily Platypodine.
II. Third tarsal joint bilobed......................... 19. Subfamily Genyocerinm.
20. Subfamily Chapuisinm. a Uncertain from description whether or not inner angle of anterior tibia is produced beyond the tarsal insertion.






226 THE SCOLYTID BEETLES.

POSITION OF THE PRINCIPAL DESCRIBED GENERA IN THE PRELIMINARY CLASSIFICATION.

Family 1pidoe. Family lpidoe-Continued.
Subfamily Cryphalina-- Subfzimily MicracinT-Continued.
Cosmoderes Eichh. Wcracis Lee.
Cr!jpli(domorphus Schauff. Hylocm-its Eichh.
1 qpod?(Iww its Westw. Stylwcopter its Blildf(l.
Sh-j)li(inodco s Eichh. Liporlhriiin Woll.
Ernoporils Thoms. Dacryodw-tas Schauff.
TrypopUu t s Fairm. Hypoborus Erich.
G-!jphalops J'keitt. Glockipliorvs Stroh.
Cryphaloides Form. Cactopin its Schwarz.
CryptartIvitto Blndfd. Subfamily Webbinve.
,ypla7iis Erich. 11. aell.
TIVoplielits Eichh. Subfa-.nil\- Xyloctoninoe.
Kyrloqe ii us Stroh. Scof"Ifloy('11(s J Iichh.
Lop;c(rt s Eichh. SwI!l1olnilims Blndfd.
Lyiwilttol-Lov. Scolylod,,s Fern
D(adrolcrits Blndfd. Xyloclowis Eichh.
Xdlocl(ldrs Fern Gton.oxylon Ilag( d.
Taphrorycl, (is Eichh. Subfamily Crypturl-inT.
Thamvio-gits Eichh. Aphonarthruin Woll.
Cocco / r qpcs Eichh. Triotonn its Woll.
Ozopewrw Haoed. Cryplat-yus Eichh.
Dryocotes Eichh. Cisur jos Reitt.
Xylrliorus Eichh. Dolvqpts l,.ichli.
Aoiwindrus Fern Dendroclon its Erich.
L'ccopt'opfcois Motsch. SubfamiIN- Plilwotribill(-e.
Cv!" /?"s ,- Z",Lipson. P111o ophlhoras NVUll.
Subfamily 1j)*111-,e- Eulytoc(ru8 Blndfd.
Pilyopllhoras Eichh. Phla oll-ibus Latr.
01oo11t(,(,ws1(1- Motsch. Dryotoin its Chap.
Acaitiiiwoiii i (-its 131ndf(l. Rellocis Czlsey.
Cli,-i tophlo tis Lee.
I P ,, De G oer. Chraimstis 1,ec.
Coriiliylin. ,. Chorlasl is Schauff.
,11(,/ (1 co / liy I 11 13 li id, fd. Carphobortis ] Iichh.
Jfoltw ('hram 11Cirsch. clwloctolois Stroh.
(V5,wocoryous Verr. Lissocl(ishfs Schallf.
Phlhon*os Vichl).
'A li.cholloccrlls ER-1111. P111-iXosollm 11111(lf(l.
Wochittocerits 111ndf(l. Icpisomlls Kirby.
TOCONS 11111(if(l. Polyrjoylois 1 Izich.
Ani ph i*cm it, its 'Fricb.
Slryullocallitis 1 ',10111. Subf-,111111NCol-1kilhis J,:rWh. xyl(chinlis
Brachyslmrltis Ferr. kissoph(tyils Chap.
(I't I. (I / h o I I I s F1 c I i h. llyltiryiis 1,ntr.
Pi-clilliobt)IS Ptichycotrs Slinrl).
villolri-lis Tonil (-tis 1,,,itr. ('11y, lopli ibl.Po (-t*1;j)s Schad. 1 qbistilms Bedel.
T//,//.,;(III ooq Lee. 1 ricrlls Lec.







IIELILMINAIIY CLASSI FICATION O1F S('QL\T011DLA. 22 7




Su ndly sk-e s(imp.-Cotnud S1114,'mu Ik m1111i o(c1I.


Acun !hojphoi-is St roh. /,I >uo p "s (Chap.
Ilylurgujps Lee. (u iusE~h
Jf!qlustes 1'ricli.( uiloVtSI)j
SublfamilNy Plwoboriuaw. L)!l11(1iI,1 / (h-ap.

IPhlu obo,-us Eric h. 1/f(i IIudd
Duct ylipa~pus Chap. S 1 (i,:i.
Famiily Scolytidl~r. Yfafly Scol V 1)~I )Ol(C

(I'r-an ,iod(1*(icic'us, Bindfd. A8cllllopb1que Imi '/!f.I' ificruborz,s l')ndfd. *4'J!) () 1 lpp.[ B,1lid.
Coptootus Chap. T1lO/I i'(15 IXII(IA(I .
Sublfami!-y il1exacoliue. Family PivoiV
Eriacopleilus Hopk.SbaiyPh poiu
Iexucobls Erich. 8 1ilh u/id "I ,s Chap 1.
Eponeudius Bindfd. Pt VlO/i III(111/8 Chap).
Problechilus Eichh.Ts rr'Sand
AricrusII~ndfd. Sqein;s(hp
Pyctwrlhrunim Eichh. C( /)IceaT/uos (Chap.
Prionoc( lc), 1,"lndfd. fdsiu( 'hap.
Rhopalopselio'i Taged. Dio1Nts (Chap.
S!if( / in bpru ),) s ilaged. ('yliwldropu ip iis Stroh.
$ph aro(P qp~s Blndfd. P/it qpvs Herbst.
Diamcrus Erich. ('rosso/arsus Chap.
Bothryperus Haged. Subfamily (ienvocerinae,
Sub family Both rosterninoe. Gen /ioC( V U S Motsch.
Pagiocerus Eichh. Sub family Chapuisina-.
('nesinus Lee. (ihapuisia Duge's.
Me1ri'ngopulpus ilaged.

GENERA DESCRIBED IN 1911-12, NOT INCLUDED IN FOREGOING LIST, BUT HERE PROVISIONALLY ASSIGNED TO THE
SUBFAMILIES.

Cycorhpiioi Haedrn------------------------ -----ryphaliw.
Xyleborites *Wickham----------------------------------------------1)o.
Pseudo thamnnurguts Egg()ers ---------- -- -o.
Neotomi cus Fuchs------------------------------------------------1lpiuna?.
Xestips ilagedorn ------------------------------------------------IDo.
Pit yokteines Fuchs -------------------------------------------------- Do.
Trigono genius Hagedorn ------------------------------------------1)o.
Allarthrum ilagedorn ------------------------------------------ Micraciiiae
Acacicis Lea --------------------------------------------------- Hylesininap.
Hapalogenius Hagedorn ------------------------------------------- Do.
Hylesinosoma Lea------------------------------------------------- Do.
Chawtophorus Fuchs ---------- ----------------------------------- Do.
Ficicis Lea ------------------------------------------------------ Do.
Minulus Eggers------------------------------------------------ilexacolinve.
Meso platypus Strohmeyer--------------------Platypodin?
Noto platypus Lea ------------------------------------------------ Do.






228 THE SCOLYTH) BEETLES.

GENERA' OF DOUBTFUL POSITION.

Mesoscolytus Blndfd. Styphlosoma Blndfd.
Phthorophloeus Rey. Acrantus Broun.
Hyloscyllus Schauff Inosomus Broun.
Dendrotrupes Broun. Araptus Eichh.














BIBLIOGRAPHY.

1758. LINNAEUS, C.-Systema naturoo per regiia tria uattirw. Ed. 10, Vol. 1, p. 355, 1761. LINNAEUS, C.-Fauna stiecica, pp. 140-143. 1762. GEOFFROY, E. L.-Histoire abre'free des iiisectes roin. i, pp. 309
fig. V.
1764. MULLER, 0. F-Fauna insectorum fridrichsdaliiia, sive Methodica description
insectorum agri fridrichsdalensis, cum characteribus geuericis et slocificis, nominibus trivialibus locis natalibus iconibus allegations, iiovis(lue pluribus
speciebus additis, p. XJV, No. 26.
1766. SCHAEFFER, J. C.-Elementa etitoinologica, Pl. CX11. 1767. LINNAEUS, C.-Systema nature. Ed. 12, Vol. 1, Pt. 2, pp. 562-564. 1775. FABRICIUS, J. C.-Systema eutomoloo-ite, pp. 59-60. 1775. DE GEER, C.-Memoires pour server 'a I'histoire des iiisectes, V(A. 5,pp. 190-198,
Pl. 6.
1776. SULZER, J. H.-Abgektirzte Geschichte der Insecteti uach dein Liiiaeischen
System, pp. 20-21, Pl. IL
1776. FABRICIUS, J. C.-Genera insectorum eorumque characters naturales, secundum
numerum, figuram, situm et proportioned omnium partium oris adjecta
mantissa speciorum nuper detectarum, pp. 211.
1776. MULLER, 0. F.-Zoologioe Danicee prodromus, seu Animalium Dani e et Norwegioe indioenarum characters, nominal, et synonyma imprimis popularium,
pp. 56-57.
1777. GOEZE, J. A. E.-Entomologische Beytridgre zu des Ritters Linn6 zw6lfteii
Ausgabe des Natursystems, Vol. 1, pp. 1 0-151.
1785. FOURCROY, A. F. DE-Entomologia Parisiensis, sive Catalogus insectorum
qu,-, in agro parisiensi reperiuntur; secundum methodum Geoffrwaiium irl sections, genera & species distributes: cui addita sunt nominal trivialia &
fere trecentae novve species, p. 139.
1787. FABRICIUS, J. C.-Mantissa insectorum sisters eorum species nuper detects,
adjectis characteribus generics, differentials specifics emendationibus,
observationibus, Vol. 1, pp. 36-38.
1788-93. LINNAEUS, C.-Systema natura-.. Ed. 13, pp. 1592-1599 and 1601-1603.
1792. FABRICIUS, J. C.-Entomologia systematic emendate et aucta, secundum
classes, ordines, genera, species, adjectis synonimis, locis, observationibus,
description ib us, Tom. 1, Pt. 1, p. 180; Tom. 1, Pt. 2, pp. 363-368.
1793. HERBST, J. F. W.-Natursystem aller bekannten in- uiid auslidndischen Insekten. Der Kifer, Th. V, pp. 81, 103, 122, 127-128.
1795. OLIVIER, A. G.-Entomologie, ou Histoire naturelle des iifsectes, Clole'opteres,
Tom. 4, No. 78, pp. 1-14, Pls. 1-11.
1800, PAYKULL, G.-Fauna suecica. 1nsecta, Vol. 3, pp. 145-156. 1801. FABRICIUS, J. C.-Systema Eleutheratorum secundum ordines, genera, species,
adjectis synonyms, locis, observationibus, descriptionibus, Tom. 11, pp.
384-395.
1802. MARSHAM, T.-Entomologia Britannica, sisters insect Britannix indigent
secundum methodum Linnaeanam disposita, Tom. 1, Coleoptera, pp. 51-60. 1802. LATREILLE, P. A.-Histoire naturelle, ge"nerale et particuliere des crustace's
et des insects, Vol. 3, p. 204.
229






230 THE SCOLY11D BEETLES.

1802. ILLIGER, J. K. 'W.-Zusdtze, Berichtigungen und Bemerkungen zu Fabricii
System Eleutheratorum, Tomus. 1. Magazine Mr Insektenkunde, Bd. 1,
pp. 306-425, with special reference to p. 367.
1807. ILLIGER, J. K. W.-Vorschlac, zur Aufnahme im Fabricischen Systeme fehlender Kiffergattungen. Mag-azin f & Insektenkunde, Bd. 6, pp. 318-349, with
special reference to p. 367.
1807. LATREILLE, P. A.-Genera crustaceorum et insectorum secundum ordinem
naturalem in families disposita, iconibus exemplisque plurimus explicate,
Vol. 2, pp. 273-2,SO.
1L13. GYLLEMIAL, L.-Insecta suecica descripta, Tom. 1, Pars. 111, pp. 33--372.
1 24. CURTIS, JOH----British entomology, Vol. 1, No. 43. 1634. WESTWOOD7 J. O.-Description of a minute coleopterous insect, forming the
tyi)e of a new subgenu dlied to Tomicus, with some observations upon the atlMities of the Xylopb,-t,),a. Trans. Ent. Soc. London, Vol. 1, Pt. 1, pp.
34-361 Pi. VII, fiors. la-1h.
1836. ERICHSON, W. F.-Systematische Auseinandersetzung der Familie der Borketikiifer (Bostrichid&-.). Archive ffir Naturgeschichte v. A. F. Wiegmann,
jl 1111'g. III Bd. 1, pp. 45-65.
1837. Kiimy, W.-Fauna, Boreali-Americana; or the zoology of the northern parts
of British America. Part 4. Tlw insects, pp. 191-195.
1839. RATZEWURG) J. T. C.-Die ForA-M (,(,Leii, Th. 1, pp. 168-232, Phs. 7-15.
18-12. 'Stettill
EA. Zto-., Jahra. 3, pp. 115-1177.
1859. TuOAi.so'-\, C. G.--;kaiidinaviens Coleoptera syiioptiskt bearbetade, Tom. 1,
pl). 146-147.
1864. PERROUD 13. P., &- MWNTROUSIEH, A.-Essai sur la faune etitomologiquo de
Kaiiala (Nouvelie-('-'aledonie) et description de quelques nouvelles ou peu comes. Ann. Soc. Liun. Lyoti, Tom. 11, pp. 46-257, Pl. 1. See
P.
1861. Ei cm1OFF, ANV.-Ueber die Mundtheile wid die Ftihlerbildung der europai. ehen
.Xyloplia(",i setis strict. Berlin Ent. Ztschr.., Jahrg. 8, pp. 11-48.
1865. THoAISON, C. G.-SkandinaviCDS 4yiioptl- kt bearbetade, Tom. 7,
pp. 34--378.
1866. LACORDAIRE, J. T.-Histoire naturelle des inseetes. Geiiera des col6optt',res,
Tom. 7, pp. 358-376.
1868. JACQt--Fu.N Du VAL, P. N. C., &- FAIRMAIRE, L.-Manuel ciaoniologique.
Geiwra des col6opt'req d'.Europe,-Vol. 4, pp. 97-108, Pls. 31-:14.
1868. C.-Syii0j),,is of the Scolytida, of America nortli of Alexico.
Ent. VA. 11, pp. 141-149.
1868. 'Syllopsisofseolyti(L(- of America iiortli of Mexi(:,(). Trans. kuier. F'itt. SOC'y Vol. 111-pp.
F')() 11-8.
1869, Cjl I'( Is, F.-Synop!- 1's de scolytidos. Meiii. Soc. Sci. U('-'-el 2 Vol. 3,
2 1: 269 (author's extra i.ssuod IS69 ).
1871. Eicmioi-j-', W.-Neue exotis(,he,,romi(.i(ion-ai-t(..,ii. Berliii Ent. Ztsclir- Jahrg.
F), pl). 131-131.
'1872, M., & HAROLD)B. Coleopterorum, \'()I. 9, pl).
2669 2702.
1875. LINDFMANV, C. allatoillische Uliter'suchillig Ober (1,18 111,C1111der l))(,rkvt&1fet% Plul, 'Soc. Imp, '.\at. Moscou, Tom. 1, 1)1). 196 21-)2, PIS. I V.
1876. ILliym-1,01)hOraof xiiierlca nortfiof Mexico. Scol tidfe.
Proc. Anier. Phil. Soc., Vol. IT), pp.3-H-3A.






PREUMINARY CLAS61FICAT101N OF SCOIATOIDI-'A. 2:11

j 1876. LUNDE. TAI;N, C.-MOTIQII' iphle (ter lloi keiik.ifer 1-1w-Liii(k. 1) crypll tloidon Tomiciden. 14il. Soc Ijiip. Nat. Nloscon, T,,m. )I, No, 1,
320-3807 0,4s. 6-55.
1878. EICHITOFF, 1 '.-Ueber (lie I.al.r. 1111d
phaous Eich. Stettin Fnt. Zl _,., JLifirg. 3 ), pp. 399 100.
1879. Eicim oi--j ', W .- Ratiol (1(,.-(-i-ipti0, eiiwwlatio o ,r-iiiii T(,iiii(-iio)r111i1, 1). 16.-).
1880. RuPE f,"FS13 F] Q6HR) (1er Ellkr Sc(d\1 id;i-, 1q). 221-2:,2.
1881. EiciiHoi.-i,, W. J.-Die enropaiscli(,ni :')1), 104.
1884. FAUVEL, A.-Sur I'idenlitil de -, lk-Imt1witeinus, Stephanod(.1-f-, (.t
llomceocryplialus. Itevue
1886. THOMSON) c. G.-[_Nole on Poly-,;-r iphu. r m(ltcla%-a Thom-, ] lu]. Soc.
Ent. France, P. L X I I.
1888. BEDEL, L.-Fatine des col6opt'res duBa.-,-in de la Seine, 'J"oni. VI, pj ). 12t.
1894. HOPKINS1 A. D.-Sexual characters M : colytidtp. Canad. Ent., k-ol. 267
pp. 274-280, October.
1894. REITTE R, E.-Bestimmuncs-tabelle der 11orkenkafer (Scolytida.) aus Eiirpa
und den angrenzendeii Litindern) 11ft. 31, pp. 40-91.
1894. RuPERTSBERGER, M.-Die biologisclie Literattir iiber (lie R'Jer Von
1880 an, mit 'Nachtragen ans friiher(,r Zeit tind einein Lar\
236-243.
1895-1905. BLANDFOI ,D, W. F. 11.-Scolytidw. Bioloo-la Centrall-Ainericana.
Insecta. Coleoptera, Vol. 4, Pt. 6, pp. 81-2 ), Pls. IV-1X.
1895. JUDEICH, J. F. & 'XITSCHE, H.-Lehrbuch dc i- mitteleuropiiischen Fi_ t7 tillsektenkunde, Vol. 1, pp. 435-5;56, fig-15. 142-178.
1896. VERHOEFF, C.-Ueber das Abdomen der Scolvtiden, ein l3eitra(, zur x-er(,Ieichenden Alorphologie des Hinterleibes dar Coleopteren. Archi%- ftir
.N aturgescbichte, Jahrg. 62, 13d. 1, pp. 109-144, fi-S. A-1).
1897. HUBBARD, H. G.-The ambrosia beetles of the United States. But. 7, n. sDiv. Ent., U. S. Dept. Agr., pp. 9-30, figs. 1-34.
1898. HOPKINS7 A. D.-On the history and habits of the -wood engraver" ambrosia
beetle-Xyleborus xylolgra-plins (Say), Xyleborns saxeseni (Ratz.)-with brief descriptions of different stages. Canad. Ent.., Vol. 30, pp. 21-29, PIS.
2-3, January.
1899. HOPKINS, A. D.-Report oil iiivesti Zations to determine the cause of unhealthy.
conditions of the spruce and pine from 1880-1883, Btil.56,W.Va.A,-,r.Exp.
Sta.,pp.197-461,figs XC1X April.
1901. BARBEY, AUGUSTE.-Les scolytides de I'Europe central. pp. 121, Pls. 18.
1902. SEDLACZEK, W.-Ueber den Darmcanal der Scolvtiden. Centralblatt Mr das
gesamte Forstwesen, Jahrg. 28, Hft. 6, pp. 241-: .63, fold. PI., Juill.
1903. GANGLBAUER, L.-Svstematisch-koleopterolo,,is(-he Studien. MiInchener
koleopterologische Zeitschrift Vol. 1, pp. 271-319.
1905. HOPKINS, A. D.-Notes on scolytid larva, and their mouth parts. Proc. Ent.
Soc. Wash., Vol. 7, No. 2-3, pp. 143-149, PIS. 4-5, October.
1906. HEYDEN, L. VON, REITTER, E., &WEISE, J.-Catalogus Coleopterorum
Europx, Caucasi et Armenia, rossica Ed. 2, column, 707-71A.
1907. TRI DL, R.-Nahrungspflanzen und Verbreitungso-ebiete der 13orkenkiifer
Europas. Entomologische Bldtter, Bd. 3, pp. 2-4, 18-22, 37-42, 53-56, 6972) 87.
1908. FORMANEK, ROMAN.-EineneueBorkenkifer-cattuii,,. Entomologischeffldtter, Jahrg. 4, p. 91, May 15.
1909. HOPKINS, A. D.-Contributions toward a monograph of the scolytid beetles.
L The genus Dendroctonus. Tech. Ser. No. 17, Pt. 1, Bur. Ent., U. S. Dept.
Agr., pp. 1-164, figs. 1-95, PIS. I-V111, June 30.






232 THE SCOLYTID BEETLES.

1909. SWAINE, J. M.-Catalogue of the described Scolytide of America north of
Mexico. 24th Report of New York State Entomologist. Appendix B.
New York State Education Dept. Bul. 455, New York State Museum,
Museum Bul. 134, September.
1910. HAGEDORN, M.-IPID. Schenkling, S., ed. Coleopterorum Catalogus, Pars.
4, p. 134.
1910a. HAGEDORN, M.-Coleoptera. Fam. Ipide. Wytsman, P. Genera Insectorum,
fase. 111, pp. 178, Pls. 14.
1910. NEWBERRY, E. A.-On Hypothenemus eruditus, Westwood. Ent. Mo.
Mag., Vol. 46 (Ser. 2, Vol. 21), pp. 83-84, April.
1910. LEA, A. M.-On Australian and Tasmanian Coleoptera, with descriptions of
new species. Part I. Proc. Roy. Soc. Victoria, Vol. 22 (new ser.), Part II,
pp. 133-150.
1911. HOPKINs, A. D.-Contributions toward a monograph of the bark weevils of
the genus Pisodes. Tech. Ser. No. 20, Pt. I, Bur. Ent., U. S. Dept. Agr.,
pp. 1-68, figs. 1-9, Pls. I-XXII, January 7.
1911. NU'SSLIN, O.-Phylogenie und System der Borkenkifer. Ztschr. Wiss. Insektenbiol., Bd. 7, No. 1-12.
1911. FUCHS, G. Morphologische Studien tiber Borkenkiifer I. Die Gattungen Ips
De Geer und Pityogenes Bedel. pp. 1-45, figs. 1-39.
1912. N:SSLIN, O.-Phylogenie und System der Borkenkiifer. Ztschr. Wiss.
Insektenbiol., Bd. 8, No. 1-7.
1912. FUCHs, G.-Morphologische Studien Uber Borkenkiifer. II. Die europ iischen Hylesinen, pp. 1-13, figs. 1-85, 3 fold. pls.
1912. SHARP, D., & MUIR, F.-The comparative anatomy of the male genital tube
in Coleoptera. Proc. Ent. Soc. London, Pt. III, pp. 477-642, Pls. XLIILXXVIII, December.

NOTE.-The next contribution toward this monograph, entitled "Preliminary Classification of the subfamily Cryphaline, with descriptions of new genera and species," will be published as Report No. 99, Office of the Secretary, U. S. Department of Agriculture.






















































ADDITIONAL COPIES

OF THIS PUBLICATION MAY BE PROCURED FROM
THE SUPERINTENDENT OF DOCUMENTS
GOVERNMENT PRINTING OFFICE
WASHINGTON, D. C.
AT

20 CENTS PER COPY














UNIVERSITY OF FLORIDA 3 1282 09229 6002
















































. 1A
if~







ok
4g
(w













'Alv











7 .-~a



All.




Full Text
xml version 1.0 encoding UTF-8
REPORT xmlns http:www.fcla.edudlsmddaitss xmlns:xsi http:www.w3.org2001XMLSchema-instance xsi:schemaLocation http:www.fcla.edudlsmddaitssdaitssReport.xsd
INGEST IEID ER0TJEHCG_G3QY64 INGEST_TIME 2014-08-02T02:50:16Z PACKAGE AA00017567_00003
AGREEMENT_INFO ACCOUNT UF PROJECT UFDC
FILES