Papers on Aphididae

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Papers on Aphididae
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English
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Phillips, W. J
Davis, John J ( John June ), 1885-1965
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Table of Contents
    Front Cover
        Page i
        Page ii
    Table of Contents
        Page iii
    List of Illustrations
        Page iv
    Introduction and description of the species
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
    Genus Toxoptera Koch
        Page 8
    Distribution of Toxoptera muhlenbergiae, feeding habits, host plants, and life history
        Page 9
        Page 10
        Page 11
        Page 12
        Page 12a
        Page 12b
        Page 13
        Page 14
        Page 15
        Page 16
Full Text


LIBRARY
STATE, PL/-NT ]BOARD
TECHNICAL SERIES No. 25, PART I.
U. S. DEPARTMENT OF AGRICULTURE,
13UREAT 013 ENTOM OLOG-V.

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



PAPERS ON APHIDID-ZE.




STUDIES ON A NEW SPECIES

OF TOXOPTERA,

WITH AN ANALYTICAL KEY TO THE GENUS
AND NOTES ON REARING METHODS.




BY

W. J. PHILLIPS AND J. J. DAVIS,
Entomological Assistants, Cereal and Forage Insect Investigations.





ISSUED MAY 4, 1912.
















WASHINGTON
GOVERNMENT PRINTING OFFICE, 1912.

23























B UREA U OF ENTOMOLOGY.

L. O. HOWARD, Entomologist and Chief of Bureau.
C. L. MARLATT, Entomologist and Acting Chief in Absence of Chief.
R. S. CLIFTON, Executive Assistant.
W. F. TASTET, Chief Clerk.

F. H. CHITTENDEN, in charge of truck crop and stored product insect in restigations. A. D. HOPKINS, in charge offorest insect investigations. W. D. HUNTER, in charge of southern field crop insect investigations. F. M. WEBSTER, in charge of cereal and forage insect investigations. A. L. QUAINTANCE, in charge of deciduous fruit insect investigations. E. F. PHILLIPS, in charge of bee culture. D. M. ROGERS. in charge of preventing spread of moths, field work. ROLLA P: CURRIE, in charge of editorial work. MABEL COLCORD, in charge of library.

CEREAL AND FORAGE INSECT INVESTIGATIONS.
F. M. WEBSTER,in charge.

GEO. I. REEVES, W. J. PHmLLIPS, C. N. AINSLIE, E. O. G. KELLY, T. D. URBAHNS,
HARRY S. SMITH, GEO. G. AINSLIE, J. A. HYSLOP, W. R. WALTON, J. T. MONELL, J. J. DAVIS, T. H. PARKS, R. A. VICKERY, V. L. WILDERMUTu, E. G. SMYT1, HERBERT T. OSBORN, PrILIP LUGINBILL, C. WV. C(REEL, E. J. VOSLER, R. N. ILson, VERNON KiNG, entomological assistants.
NETTLE S. KLOPFER, ELLEN DASHIELL, preparators8. MIRIAM WELLES REEVES, collaborator.
II

























4
CONTE NTS.

Page.
Introduction ------------------------------------------------------------Description of the species -------------------------------------------------- I
Genus Toxoptera Koch ---------------------------------------------------- 8
Key to the genus ----------------------------------------------------- 8
Distribution of Toxoptera muhlenbergix ------------------------------------- 9
Feeding habits ----------------------------------------------------------- 9
H ost plants --------------------------------------------------------------- 9
Life history -------------------------------------------------------------- 9
Continuous-generation experiments ------------------------------------ 9
M olting ------------------------------------------ -------------------- 13
Fecundity of the summer forms ---------------------------------------- 13
Age when individuals begin reproducing ------------------------------- M
Length of life of the viviparous forms ----------------------------------- 1-3
The sexes ------------------------------------------------------------- 13
Place of opposition --------------------------------------------------- 14
Fecundity of the oviparous females ------------------------------------- 14
M ortality of eggs ------------------------------------------------------ 15
Rearing methods ----------------------------------------------------- 15




























ILLUSTRATIONS.


PLATE.
Page.
PLATE I. Outdoor rearing shelters ----------------------------......................................... 2-------TEXT FIGURES.

FIG. 1. Toxoptera muhlenbergix: Winged viviparous female and antenna...... 2
2. Tozoptera muhlenbergix: Wingless viviparous female .................. 3
3. Toxoptera muhlenbergix: Wingless male and antenna ................. 4
4. Toxoptera muhlenbergix: Wingless oviparous female, antenna, hind
tibia........................................................... 5
5. Toxoptera muhlenbergim: Eggs....................................... 6
6. Toxoptera muhlenbergix: Eggs deposited in curled leaf sheath---------......... 13
7. Lamp chimney molting cage used in rearing aphides ................. 14
8. Lamp chimney generation cage used in rearing aphides............... 15
9. Lamp chimney stock cage used in rearing aphides.................... 15
IV












U. S. D. A., B. E. Tech. Ser. 25, Pt. I. Issued May 1, 1912.

PAPERS ON APHIDIDzE.


STUDIES ON A NEW SPECIES OF TOXOPTERA, WITH AN ANALYTICAL
KEY TO THE GENUS AND NOTES ON REARING METHODS.
By W. J. PHILLIPS and J. J. DAVIS,
Entomological Assistants, C(Jrcal and Forage Insect Investigations.
INTRODUCTION.
Toxoptera muhlenbergix has been under observation since the summer of 1908. On July 24 of that year Mr. V. L. Wildermuth, of this bureau, found this aphis at New Paris, Ohio, on a species of Muhlenbergia. It was thought at the time that it was Toxoptera graminum, to which species it bears a very close resemblance. The senior author found the same aphis at Richmond, Ind., later in the month, placed it in rearing on Muhlenbergia, and obtained the sexes in October. From the sexes it was very evident that the species was not T. graminurn, as the male is wingless. Since T. muhlenbergix bore so close a resemblance to the destructive "green bug," a species that the senior author was then studying, he has also kept the former species under observation since that time. The junior author has named and described the species and has also drawn up a key for the identification of the members of this genus. The authors wish to thank Mr. Philip Luginbill, of the Bureau of Entomology, for his assistance in rearing through consecutive generations of this species.

DESCRIPTION OF THE SPECIES.
TOXOPTERA MUHLENBERGLE N. SP.
WINGED VIVIPAROUS FEMALE.
(Fig. 1.)
Head brownish, thoracic plate dark brown, and abdomen pale green. Usually a small pale-yellowish area on the abdomen around each cornicle. Eyes black and ocelli dusky. Antennoe blackish excepting segments I, II, and the extreme base of III, which are pale brownish; slightly imbricate, 3 to 7 circular sensoria in a row on segment III, the usual one near the distal end of V, and several
1





2 PAPERS ON APHIDID2E.

small ones surrounding a larger one at distal end of base of VI; total length about equal to that of the body; segments III and filament of VI longest, the latter being slightly the longer of the two; IV and V subequal, their total length, being subequal to III; base of VI about three-tenths the length of the filament or one-third of III. (See fig. 1, b.) Beak reaching slightly beyond the coxm of the first pair of legs. Legs dark brown excepting the basal one-third or onehalf of the femora and tibia. Wings with the discoidal vein oncebranched, the branching being about two-thirds the distance from the base to the tip of the wing, the basal end not contiguous with the costal vein (occasionally one wing with the discoidal unbranched, and in one case the branching was at the extreme tip of the wing);

















FIG. 1.- Tozoptera muhlenbergiz: a, Winged viviparous female, greatly enlarged; b, antenna of same, more enlarged. (Original.)
veins dark brown. Lateral abdominal tubercles inconspicuous. Cornicles pale green, very slightly swollen in the middle, subequal in length to the style. Style pale green, and slightly longer than the hind tarsi.
Measurements (from specimens mounted in balsam): Length of body, 0.7999-0.9090 mm., average, 0.8471 mm.; width, 0.29090.4181 mm., average, 0.3526 mm.; length of wing, average, 1.88
0.18 mm. t- )
mm.; width, average, 0.636 mm.; antenna, I, 0.05 mm.; II, 0.041 mm.; III, 0.2119-0.2608 mm., average, 0.23 mm.; IV, 0.0978-0.1385 mm., average, 0.1124 mm.; V, 0.1222-0.1467 mm., average, 0.1325 mm.; VI, base, 0.0652-0.0896 mmn., average, 0.0787 mm.; VI, filament, 0.22-0.2689 mm., average, 0.2509 mm.; average total, 0.8955 run.; cornicles, 0.09-0.12 mm., average, 0.0986 mm.; style, 0.0978-0.1141 mm., average, 0.1048 mm.; hind tarsus, 0.0978 mm.





A NEW SPECIES OF TOXOPTERA. 3

Described from eight living specimens received from W. J. Phillips collected on Muhlenbergia at La Faye'tte, Ind., September 9, 1909. Types mounted on four balsam slides, in the collection of the Bureau of Entomology, U. S. Department of Agriculture.
WINGLESS VIVIPAROUS FEMALE.
(Fig. 2.)
Head and body entirely pale green, the head being slightly paler than the thorax and abdomen. Eyes black. Antenna[ segments I, II, and III very pale brownish, IV pale at base and gradually changing to dark brown or blackish; total length slightly more than half that of the body; filament of VI largest, it being about four times the basal portion of VI; III three times the length of IV and threefourths filament VI; IV and V subequal, V being slightly the longer. Beak reaching the coxve of the
second pair of legs. Legs
pale excepting the tarsi and
distal ends of the tibiae, which
portions are blackish. Abdominal tubercles as in the
winged form. Cornicles and
style pale, with a slight greenish tint, and not unlike those
of the winged female in form.
Measurements (from specimens mounted in balsam):
Length of body, 1.1308 mm.;
width, 0.5198 mm.; antenna,
1, 0.0489 mm.; II, 0.04 mm.; FIG. 2.- Toxoptera muhlenbergie: Wingless viviparous 111 0.148-mm.2;0.04 am., female. Greatly enlarged. (Original.) 1II, 0.1548-0.2037 mm., average, 0.1825 mm.; IV, 0.0815-0.1141 mm., average, 0.0994 mm.; V, 0.1059-0.1141 mm., average, 0.1108 mm.; VI, base, 0.0652-0.0815 mm., average, 0.0684 mm.; VI, filament, 0.2119-0.2771 mm., average, 0.2477 mm.; average total, 0.7977 mm.; cornicle, average, 0.1385 mm.; style, 0.1141 mm.; hind tarsus, 0.09 mm.
Described from six living specimens collected at La Fayette, Ind., September 9, 1909. Types mounted on four balsam slides, in the collection of the Bureau of Entomology, U. S. Department of Agriculture.
WINGLESS MALE.
(Fig. 3.)
Head dusky green to blackish, prothorax pale green, thoracic plate dark to blackish green, and the abdomen pale greenish yellow. Eyes black. Ocelli present as in the other forms. Antenme blackish, excepting the two basal segments, which are pale dusky; irregularly placed circular sensoria as follows: 22-23 on III, 17-24 on IV, 11-17





4 PAPERS ON APHIDIDM.

on V, and the usual ones at the distal end of base of VI; subequal mi length to that of the body; III the longest, it being nearly twice as long as IV and four times base of VI; IV and V subequal, and base of VI slightly less than one-third of filament of VI. (See fig. 3, b.) Beak reaching just beyond the coxa of the second pair of legs. Legs pale, excepting the tarsi and distal ends of the tibiae, which- are blackish (in some specimens the basal ends of the femora are pale and the remainder gradually becoming dusky toward the apices, tibiae dusky excepting the blackish tips, and the tarsi black). Cornicles and style whitish green.
ALMeasurements (from specimens recently
mounted in balsam): Length of body, average, 1.127 am.; width, 0.4143 m.; antenna, I, 0.057 num.; II, 0.0489 mm.; III, 0.2934-0.3504 mm., average, 0.3209 mm.; IV, 0.1467-0.22 mm., aver- age, 0. 1793 mm.; V,
0.1548-0.1874 mm., average, 0.1712 am.; VI, base, 0.0733-0.0896 mm., 6 average, 0.0815 mm.; VI,
filament, 0.2445-0.3097 FI. 3.- Toxoptera muhlenbergiw: a, Wingless male, greatly en- mm., average, 0.269
larged; b, antenna of same, more enlarged. (Original.)
mm.; average total, 1.1278 mmn.; cornicles, average, 0.1074 mm.; style, average, 0.1026 mm.; hind tarsus, 0.1074 mm.
Described from seven living specimens. Types mounted in balsam on five slides, October 13, 16, and 18, 1909. In the collection of the Bureau of Entomology, U. S. Department of Agriculture.
WINGLESS OVIPAROUS FEMALE.
(Fig. 4.)
Head pale yellowish and the thorax yellowish green. Abdomen pale greenish, the sides being decidedly pale green and the median dorsumL more of a yellowish, this latter being due to the yellow eggs within. Eyes black. Antenna With segments I and II concolorous





A NEW SPECIES OF TOXOPTERA.

with the head; III pale but slightly dusky; IV and V pale dusky; VI blackish, slightly more than one-half the length of the body; filament of VI longest, it being one-fourth longer than 1II; 111 and IV subequal, and base of VI a little more than one-third of I1. (See fig. 4, b.) Beak not reaching to the (oxal of the second pair of legs. Legs pale, excepting the distal ends of the tibia,, which are dusky, and the tarsi, which are black. Hind tibia (fig. 4, c) swollen and bearing 15 to 21 rather large but inconspicuous sensoria. Cornicles cylindrical, pale yellow or greenish yellow, and about one-third longer than the hind tarsus. Style concolorous with the cornieles and slightly longer than the tarsus. The position assumed by the oviparous females is similar to that of other species, namely, with the hind tibiv held back along the abdomen, and the abdomen
tilted upward.
Measurements (from specimens recently mounted in balsam): Length of body, average, 1.796 mm.; width, average, Q.7855 mm.; antenna, I, 0.057 mm.; II,
0.048 mm.; 111, 0.163-0.2363 mm.,-average, 0.2052 mm.; '.
IV, 0.0978-0.1467 mm., average 0.1254 mm.; V, 0.1141-0.1548 mm., average, 0.1368 mm.; VI, base, c
0.0652-0.0815 mm., average, 0.0748 min.; VI, fla- FIG. 4.- Toxophra muhlenbcrgi: a, Wingless oviparous ment, 0.2282-0.29 min., female, greatly enlarged; b, antenna of same, more enaverage, 0.2589 mm.; aver- larged; c, hind tibia of same, more enlarged. (Original.) age total, 0.9061 mm.; cornicles, average, 0.1596 mm.; style, average,
0.1237 mm.; hind tarsus, average, 0.1042 mm.
Described from 12 living specimens. Types mounted on six slides. October 8, 13, 16, and 18, 1909. In the collection of the Bureau of Entomology, U. S. Department of Agriculture.
EGG.
(Fig. 5.)
Pale yellowish when first laid, gradually changing to pale green, then dark green, and finally to jet black. They are deposited singly on the leaves of Muhlenbergia. Form ellptical-oval. Measurements: Length, 0.56 mm.; width, 0.26 mam.
264590-12-2





6 PAPERS ON APHIDID2E.
STEM-MOTHER.1
First instar (before first molt).-General color dark nile-green; head, beak, antenna, and legs very dark gray, almost black; cornicles very dark, small, and incoiispicuous; eyes black; antenna 4-segmented.
Measurements (from two specimens in balsam): Length of body, 0.49 mm.; width, 0.20 nmm.; antenna, I, 0.0326 mm.; II, 0.0326 mm.; III, 0.0896 mm.; IV, base, 0.0407 mm.; IV, filament, 0.0896 mm.; total length, 0.2851 mm.
Described from two specimens. Types on two balsam slides in collection of the Bureau of Entomology, U. S. Department of Agriculture. La Fayette, Ind., 1910.
Second instar (before second molt).-General color blue-green, the head having somewhat of a grayish cast. Antennm 5-segmented; the three distal segments very dark, almost black; the basal segments pale gray. Beak black at tip, reaching to coxa of the third pair of legs. Legs pale, excepting tarsi and distal portions of tibia, which are black. Tips of cornicles black, small, and inconspicuous as in the first instar.
Measurements (from two specimens re. cently mounted in balsam): Length of Fm.5.-Toxoptera muhlenbergiz: Eggs. body, 0.54 mm.; width, 0.245 mm.; anGreatly enlarged. (Original.) tenna, 0.0326 mm.; 0.0326 ; ,
tenna, I, 0.0326 mm.;, 0.36m. III, 0.065 mm.; IV, 0.0489 mm.; V, base, 0.0489 mm.; V, filament, 0.114 mm.; total length, 0.342 mm.; cornicles, 0.0326 mm.; hind tarsus, 0.0733 'mram.
Described from two specimens. Types on two balsam slides in the collection of the Bureau of Entomology, U. S. Department of Agriculture. La Fayette, Ind., 1910.
Third instar (before third molt).--General color of body pale green, eyes black. Antenna 5 segmented, entirely dusky, but darker near the tips, a single sensoriumni at the end of IV and several at end of base of V. Beak not reaching coxm of third pair of legs, the tip black. Legs pale greenish gray, excepting the joints and distal portions of tibia, which are dusky, and the tarsi, which are black. Cornicles concolorous with body, excel)tming tips, which are d(usky.
Measurements fromi two specimens recently mounted in balsam): Length of body, 0.88 mm.; width, 0.40 mm.; antenna, 1, 0.0407 nmn.; II, 0.0326 mrm.; III, 0.125 mm.; I 0.07,3 nn.; V, base, 0.0652 mnu.; V, filament, 0.14 mm.; total length, 0.4768 rm.; cornicles,
0.049 mnm.
Described from two specimens. PTyi)pes on1 two balsanm slides, in thelw collection of the Bursu of E4ntoology, 1. S. Department of Aglicultlur. La layette, I.,9.
1tColor notes of I ithe five instars of the stem-mot her were made ht'by Mr. Phillips






A NEV SPECIES OF 'TOXI)PTFIA. 7

Fourth instar (before fourth iomlt).-General color pale green, tie head being slightly paler than other parts of the bod, nd i th abdomen having somewlmt of a ,uottled appeearane, due to tle presence of young within. Beak not reaching (coxwU of thlirn] pair of legs, black at tip. Eyes black. Antenna' 5-segm ente(I (olle speci.men showed six segments plainly), segment II with a construction. a little beyond the middle, indicating the point where it divides at the next molt; the two distal segments almost or quite black, tile others dusky, shading into greenish gray at the base; sensoria as in the preceding instar. Legs greenish gray, shla(ling into dusky near extremities; tarsi shining black, distal portion of tibiw, and joints quite dusky. Cornicles concolorous with abdomeii, excepting ti)s, which are dusky. Style slightly )aler than body.
Measurements (from two specimens recently mounted in balsam): Length of body, 0.90 mm.: width, 0.3912 mim.; antenna, 1, 0.049 mm.; I, 0.04 mm.; 111, 0.122 mi.; IR, 0.065 mm.; V, base, 0.057 mm.: V, filament, 0.114 mm.; total length, 0.447 mm.; cornicles, 0.049 rm.; hind tarsus, 0.0896 mm.
Described from two specimens. Types on two balsam slides, in the collection of the Bureau of Entomology, U. S. Department of Agriculture. La Fayette, Ind., 1910.
Fifth instar (adult stem mother).-Before the birth of any young the adult is pale green, but gradually the color deepens to applegreen. As in the preceding instar, the young show through the body wall, giving the abdomen somewhat of a mottled appearance. Usually there is a small yellowish area around each cornicle. Head much paler than body, and with a grayish tinge alt anterior end. Beak barely reaching coxe of second pair of legs, black at tip. Eyes jet-black. Antennae less than one-half the length of body, segments III and filament of VI longest, they being subequal, but filament VI usually slightly the longer of the two; IV about two-thirds or less the length of III; IV and V subequal; base of VI about one-half the length of filament; the two basal segments concolorous with head; III dusky, shading to blackish at apex; the remaining segments black. Legs greenish gray, excepting the joints, which are dusky. Apices of tibie very dusky, and tarsi shining black. Cornicles pale translucent, and dusky at tips. Style pale translucent, sometimes dusky, and with a frosted appearance. All stages, including adult, are more or less pruinose.
Measurements (from five specimens recently mounted in balsam): Length of body, average, 1.34 mm.; width, average, 0.69 mm.; antenna, I, 0.057 mm.; 11, 0.040 mm.; IIi, 0.14-0.175 mm., average, 0.155; IV, 0.08-0.1059 mm., average, 0.0945 mm.; V, 0.0978-0.1222 mim., average, 0.10 mm; VI, base, 0.073-0.089 mm., average, 0.08 mm.; VI, filament, 0.14-0.195 mm., average 0.171 mm.; average, total, 0.6975 mm.; cornices, 0.11 mm.; style, 0.135 mm.; hind tarsus, 0.10 mm.






8 PAPERS ON APHIDIDE.

Described from five specimens. Types mounted on five balsam slides, in the collection of the Bureau of Entomology, U. S. Department of Agriculture. La Fayette, Ind., 1910.
Genus TOXOPTERA Koch.
Seven species of the genus Toxoptera have been described, the one described in this paper being the eighth. All, with the exception of this last and T. caricis Fullaway, occur in Europe, while only three (T. graminum, T. aurantii, and T. muhlenbergiw) are known to America. T. caricis was described from specimens collected in
lawaii. The following table may be of service to other workers:
KEY TO THE GENUS.
I. General color .of apterous viviparous females black or dark rusty.
(a. Apterous females dark rusty; margin of abdomen' bearing tuberculate hairs;
wing veins pale fuscous, stigma white..................scirpi Passerini.
On Scirpus specierum and S. lastris.
aa. Apterous females black; margin of abdomen not bearing tuberculate hairs.
b. Sixth antennal segment of winged female equal to one-sixth the terminal
filament; wing veins and stigma fuscous; fork of cubital vein arising
before the point where the stigmal vein originates.
aurantii Boyer de Fonscolombe.
On orange, citron, and Camellia.
Syn. T. aurantie Koch.
T. camellia Kaltenbach.
Ceylonia theaccola Buckton.
bb. Sixth antennal segment of winged female equal to one-fifth the terminal
filament; wing veins and stigma not fuscous, pale yellowish; fork of cubital
vein arising opposite or beyond the origin of the stigmal vein.
clematidis Del Guercio.
On ornamental Clematis.
II. General color green, yellow, or brownish yellow.
a. Body of wingless viviparous female dark green, variegated with shining black.
Stigma green......................................c ariegata Del Guercio.
On Rhamnus alaternus.
aa. Body uniformly green, yellow, or brownish yellow.
b. Style black, at least in the winged viviparous female.
c. Body of wingless viviparous female uniformly dark green; style black.
alaterna Del Guercio.
On Rhamnus alaternus.
cc. Body of wingless viviparous female brownish yellow, paler at the margins;
style darker than body color; cornicles very large, extending beyond tip of style, much constricted at base and apex............caricis Fullaway.
On Care sp.
bb. Style green, yellow, or but slightly dusky.
d. (C'ornicles uniformly pale greenish or yellowish green; usually a small
yellowish area on the abdomen at base of each cornicle; the media (third discoidal) branching at about three-fifths the distance from the base of the vein to the tip of the wing; antennal segments III and "VI filament" subequal. Males wingless...muhlenbergi n. sp.
On Muhlenbergia sp.
dd. Cornicles blackish at tip; the media (third discoidal) branching at
about one-half, or less, the d( instance from the base of the vein to the tip of the wing; antennal segment "VI filament" noticeably longer than III. Males winged....... ..........-----graminum Rondani.
On wheat, oats, rye, barley, and various grasses.





A NEW SPECIES OF TOXOPTEIIA. 9
DISTRIBUTION OF TOXOPTERA MUHLENBERGIM.
This aphis has I)ven found through northwest niii and west-centrl Ohio and through east-central 4tnd northern Indiana. It, probably may be found in any location in which iuillnria flourishes.
FEEDING HABITS.
Individuals of this species concentrate on the tender shoots and are rarely found on the tough leaves unless the plaints are badly infested. They congregate in the curled central growing shoot. As this leaf expands and unfolds, they go to the younger curled leaf just below this. When in great numbers, they cause these tender shoots to wilt and turn yellow.
HOST PLANTS.
Up to the present time Muhlenbergia sp. appears to be the normal host, though this aphis often goes to bluegrass (Poa pratensis) when first hatched, since the young sometimes appear before Muhlenbergia has started growth. Coloies have been established on wheat, though they do not appear to thrive very well on it.
LIFE HISTORY.
As stated previously, the sexes were reared in October, 1908, at Richmond, Ind. A number of eggs was obtained from these females and they were taken to La Fayette, Ind., in March, 1909, but failed to hatch. Later on in the year these aphides were found in abundance and rearings were begun, with the result that a large number of the sexes and an abundance of eggs were obtained in the fall.
CONTINUOUS-GENERATION EXPERIMENTS.
About 1,000 eggs were collected in the fall of 1909 with the hope of getting stem-mothers to start a series of continuous generations. None of these eggs hatched, however. Large numbers of eggs were found in the field and from these the continuous-generation series were started; that is, starting with the stem-mother and isolating her first born and the first born of each successive generation until the sexes appeared; and a second series, consisting of the last born from the stem-mother and the last born of each successive generation until the sexes appeared. By adding the number of first and last born generations and dividing the result by 2 we are able to arrive at the approximate number of generations that would be produced during the year. Much other data would also be accumulated in this way on the daily production of young, the maximum and minimum number of young produced, and the average length of life.
The table following gives in detail the consecutive generations of the first and last born series, starting with a stem-mother that hatched March 28, 1910.








10 PAPERS ON APHIIDA.

Table of consecutive generations of Toxoptera muhlenberiax.

[b=born; d=died or disappeared.]

Tern- Last-born generation4
pera- First-born generation series. .
ture.













MTar. 2S '-4 53 i ).b .... ..... ... .. . ...
M ar. 29 1)4 571 0 .. .. .. ... ----.. -- -. .. .. ..
Mar. 30 7 ,0 .
M ar. 31 73 42 0 ---- --- ... .. .... .

pr. 63 37 -- -. --
"pr. 2 6 7 3 9 0 .... .....
.--- -- .. .. .... ..
A nn 5 73 42 ..... ---- ---- ---- -I I I
AFpr 4 7 1 5 .. .. .. ..... .Apr. 2 81 39 0 ... ... ......... .......... ........
Mar.3 76 6 0-------------------------------- ---- ---- ---- ---------ar.31 73 42 .. ............. .........


Apr. 63 3 0----------------------- --- ------ ------- .... ... ....
Apr. 2 69 39 0-.---.----.--------.
Apr. 13 73 42 0 _----------------Apr. 14 7:3 43 0- ---.------Apr. 15 80 50 0 --------- ----..
A pr. 16 7 1 9 0 2...... ....- ----.. ..
Apr. 17 46 3 0 0-0 .---.--------.-Apr. 18 30 ---------.. .. ......
Apr. 197 4 2 0 ------ -------- ......

Apr. 1 1 357 0---------- -- ....-..------------Apr. 12 0 43 2 b ---- --- -- -------- -----

Apr. 1 68 32 0 0.------------ ---...-....-....
Apr.15 80 32 0 ....----.-------Apr.6 779 3 --.------------------------------------ ---- ------A pr. 2 4 3 7 0... 0...... ......-
Apr.18 48 30 ----------------. ...--- .
Apr. 2194032 00 --------- -- --- --- ---A-pr. 226 2 --- 3 0 ... ......--- ----- --- -- ------------- -------Apr. 20 47 350 -- ... Apr. 2 31 26 ...... .. ... .....
,aypr. 65 30 0 0 ------------------ -- ------------ ... ------ ----,aypay 2 6 97 44 359 .. .. .... .._ .... ..... ......... ... .
A pr.22 643350 0------------------------------------------------ --;k p r 2 8. . I
M ay..9............ ... ..
apr.2 7 1 26 0 0.............. ... ... ... .. .. ... ... ... ... ... .

ar.2 5 4300 0 ... .... .. ..
A 2 4... ... ..... .............. ..... .......

Apr.2 71 46 0 0- - --.... ....... .... .... .
Apr.30 82 5.. 3... 0 ----- --- ----- ------ ---May~~~ ~ 1 6 50 0 ----------------------------May 2 71 592 0 ------- ------- .... ... 0 -0



Nfav :3... .. ....[ .... .... .. 0
May .3 I'9 4:3 .... I .---------------------------------May 4 1 3 34 0 0- .. ... .0.... .... ...0- .
M ay 55 6.. 3 0 --- -_------------------------------------.............
May 6 59 41 .... 1 0-------------------------------------------0-----------------.
May 7 62 4.5 2 ... 2.. -0
May 8 5:1 46 .. 0... 0 .......



M a3 ....4.4.0 .... ... ... .... ....... ..
May 19 5 49 0 0 .....
May10 72 4i 2 .... ...-.....




M a....8 6 .... -- ....... ....
M ay I1 73 54 .... 02 ... ............ ....--- --May 12 5 5 35-. 0 0 ...-. ..........
M ay 13 57 36 0 ....o ....... ...
May 14 55 :14 5 .... 1 0.......0





May 15 5 405 --\ J----------------------------May 16 5 49 1 -0 .....- ... ..
My 171 2 0 -- -. May 18y G4 49 --4 ---------------------0-------May2 1 0 714 1 .. .... ..- .... o............
Maye2 1 41 0-----.... ...
M Io 69 44 :-w 1 1 0 -------. .---------------0........
May 2o 7 "'j 41 I 1 o' 0---------------------Mfa y 21 718 1 ( 0 ------------------- --- --Mfay 22 7 2 0. ..1 ......... .... 0 0------------------------May'I~~~ 0U 41. ... ... --0-------JMn v o 2f) 61 4 0 ...
Juney 2 .. 41-------------0--------------







A NEW SPECIES OiF TUX0VFEIIA. 11

Table of consecutive generatiotis of Toxopferu mi C/ e w (n I I il Ii wd.


Perai- 'rtbr eea i tr' Laist-born l i rjJfl
ture.



............


U

El ~- Z


0F. 0 F
June 3 5939.... .......0. ...1
June 4 61 44 ... ~ 0 ... ..
June 565 54 ..... 0 0.. ... 0
June 6 70 46............. 0......------- K....00
June 7 71 40..........0 ...J .. ... 00.............1
June 9 77 56 -- -0- ---- -0.......... ..
June810702 53.... .... ......0........................ .... 0I......
June 107 0 53.... .... 0.. 1
June 11 70 45.... .......... 1 b ... .. ....
June 13 79 52 -- --0 -- -- -- -June 14 83 1............2 0 ....0 ..
June 15 81 53............5 0I 1.1.1 ... ... -- 1---
J u n e 1 6 8 7 57. 2 0 -- --.-.- -- -'
June 17 90 61............3 0 ---1 2
June 18 91 63..... .... .....1 0..
June 19 92 63............0 0 --- 2----June 20 94 60 ----.......0 0 -- ---.-
June 21 90 65...........d 0....................... 0.... ......
June 22 93 6 5.......... .. 1 ---............- 0........ ......
June 23 94 68........... ..2 0.................... .. 2 .... .... ... ...
June 24 969............ 2 0. .................. .....--2 .... ....
Jun6 25 92 13................0 o ---......--- 1
June 26 91 lJ2.............. ..0 0....................-K--- 3
June 27 9668................o 0........... .. --- -June 28 75 62.............. 0 0. ----. .. -- -- 3 -June 30 86 64.......... 1 0 0 0 --- 0July 1 9368........... 4 0..- --- 0
July 2 94 72 ---3 0 --- 1- ----July 3 82 71.. ..0 ....
July 5 75 59 ----U --- --.2...--. ---1 -- 0 .
Jul 486 0....... .... ...
JulyV 6 85 64 .. .. .3 1 0-- ---- --- 0 0
July 7 86 66 .. d 5 0 ..... d o
July 8 8865..........0 o......................
Jul 9 27 ............... 0...... .... .... ............. ..0. ...
July 1092 19............ (..........--------.... .... ..........
July 1 16982-58 -----. ----.-. --.-.-- 1 10 ... .... .... .... ............ 0....
July 12 86658...-..---.---.-.--.....1.10... 0 .... ... ...
Jul'y13 86 G05.......... I.......
July 14 83 61...... ....... ...... 1 0 0 --- ----- --0
July 15 88 68............... ........- d 1 0 ----- ------. ..0 .... .
July 16 8968.................. .....2
July~~~~ 1876.f0........ ...... ........0.........-July 17 859 . ... ( S -- -----:----- -- 2 0 ..... ... ...ff 0 .
July 19 77 54.... .... .... .... .... ....0 0.............. 0 .....
July 807 54.............0 0 ........ .... .... .... .... 0...... ...
July 21 83 591........ .... .... .... ....2 ~---- ---- 11...... 0........
J u l y~~~~~- 2 2 3 6 . . ... .
July 23 83670............................-2 0 -----------........ .... ........ 3 ..... ..
July 2 5 8 9 7 63- -- d 0 -- .. .
July 24 88 73..............- ..... .... ....2 0 .... ---- -- ---- ...
July 27 90 70 . .0-- --- -- - .
Jul v 26 9164............................0.0. ..
July 28 946..................................
July 2966.............1 0..........................2'0
July3 844................... 0....................... 0. .
July 3183 5.... .... .... .... .... ......1 000
Aug. 12 SO 53..-.... .... .... .... .... ....(1 O 0 0.....
Aug.y 30 90 64...............3.....................0
Aug. v 53 83 54.. . .. 2-- -- -- -1)--- -- ... .. 0.. .
Aug. 41 0 ........ .............. ...dl--- 0.... ......... .... ............d 0 0 .. ..
7860.................... o .... 0
Au 6 82 5. .. ....... .... .........01-- -Aug. 8 74 64 ---.-.-. --. -.... ... 1 -- --{-iii::I~: 2 { j
A~~~~~~ ~ ~ ~ ~ ate of *it uncertain.- ---- -- .. .. d i -- -








12 PAPERS ON APIDJID2E


Table of comsecu tir-e generations of Toxoyltera muheibergw Cniud

Temi- Ls-ngnrto
pera First-born generation series.sei.
tare.



0~ 14
D 0
-~
4)a CS.. a
~ el~ ) A)4
~ 4 4) 4) zi ) :,
C.) UO 73




OF. OF.
Aug. 986 59--------------------------------...1 0 ......-.
A ug. 10 77 55-------------- -------- ------0 -0---------------------Au.1 56--------- ------ --------1 0------------ ------ ---. ... ... .
Aug. 12 85 55---------------- ---- ---- ---2 0
A ug. 13 87 56--1...--------..---- ---- ---- ------2 0Aug. 14 87 56----.---- ---- -------------0-----------.4
Au.59 7---------- ---- ------------0 --6 ---.... ..)...
Aug. 1487 92 71 ------ ----I..----A~ug. 15982------ 67-- 62)-- ---------
Aug.2 90. 64....---- ... 3. 0 ------Aug.2 86 2 58------------... .<.... ..
Aug. 27 1465------ ... 00------------------. 23
0----- ---- --------..
A ug.2 189264----- --- --- -------------0 5 0 ----- ---- ---- ---- ----2
Au.58 74---------- ---- -- -------2 5 0---- -------Aug 268 7---- ---- ---- ---- ----------------------2 --Aug. 27 0 478----- 00 ....
Aug. 218 4 7 5 50 --- ---- -- ---- ---- 0
Aug.2 980 64 0
A ug. 2308556
Sept 1.. 80. 60.............
Sept. 34 77 64 .... 0. 2 0) -- 2 l
Sept. 45 86 56- -- --- -- 1 .. --
Sept. 56 804 67 --- -- -- -- 0 1 .. ..... .. ...Sept. 68704 7 .. --- -------- ---- -- ---- ---Sept. 79 82........ .... .... .......1.... .... .... 2 1- ..... ....
Sept. 90 85 60.......... ----- .. .. .. .. .. .. .. ..
Sept.1 0 6 46 .- -- -- -4--- --- -- -. .. .
Sept. 1 8 69 04 --- .... -. .- --- 0 0. .. .
Sept. 12 80 56 1, -n
Sept. 13 79 59..........2 ....... .. ..
Sept.14 861 53-------------------------------------------.. 0 .... ........... .....
Sept.15 8 67----- ---- --------------------------02
Sept.16~~~~-- 734------------------------------0Sept.1 77 48-----------------------------.......-------------2 0............


Sept. 18 80 5-------------------------------- ---------2 10 .. ..0
Sept.20785 58--------------------------------0 1----- ------- --Sept.210 79 46. --- -- ---- ---------- ------ -0 2 0----------------- 0
Se t 1 604 ..... .. .. .......-...1--...-..-.0Sep t.2 8 56 ----- .... ..0 --... -.. --... --... -----(0
Sept.214 7--------- ---- ---- --------- ---- ---- ---- ---- ---------0-----------------.
Sept.265 68 46 -- .... .... .. .... ...
Sept.276 72 51 ....--,--- 0 0.......... ...0
Sep t.2 657 42..................... ... .... .
---- ----------S ep t. 29 70 58 .... .... ......... .... .... .... .. .. 0 1 0 .......*-
Sept. 30 7854 49..... o.............. .......... .. d 1 o.. ....
Ocpt. 13 8 54------------------.. ...... ...... 0...............
Ocpt. 24 78 48-----------------------------------------......-....2 0 .... .... .
Ocpt. 35 77 57------------------------------------------.. .---.-- 1-0 ----.--Oct. 48465.......................
Set. 26 72 5..... .... .... ......
Ocpt. 67 73 514 .. ..... .. ... 0 0


Oct. 24 65 47------------------ 0 ... .... .... ....
Ocpt. 29 70 43................... ...... .
Oct. 1 0 64 40--------------------------------------------- 0 ....
Oct. 11 784S.... 42----------------------------------------Oct.1 3 -7 57----- -----.......-......-.-..--.
Oct 4 84l C5 n.. w. -D e Oct 3.. .er .o... .e.e..e Int t ... ..e








Tech. Series 25, Part 1, Bureau of Entomology, U. S. Dept. of Agriculture, PLATE



'0










L -12









4[ ..






OUTDOOR~'0 0ERNGSELES








A NE V S1i E S OF T()XOPTERA. 1 3

From this table it will be seeI that there were 14 gererators of
the first-born series and 7 of the last born. This would give approximately 10 generations for the year.
~M OLTI N(;.
.... NNC.
In 1909 some molting experiments were coi( UCte(l. Five in(lividuals that had just been born were placed in a specially prepared
-cage, as shown in figure 7, and observed throughout the molting
period. After becoming adult it was found that there were I male and 1 oviparous and 3 viviparous females among these 5 in(ivi(uals.
In 1910 observations were also made on a stem-mother to note the
number of molts. Of the 6 individuals,
all molted 4 times without exception.
FECUNDITY OF THE SUMMER FORMS.
The 19 individuals concerned in the
generation series produced 311 young, or an average of 16.3 young each. The maximum number of young produced by a single individual was 35. The maximum number of young produced by any individual in a single day was 5.
AGE WHEN INDIVIDUALS BEGIN REPRODUCING.
The period between birth and reproduction varies greatly, being longest in the spring, when it varies from 15 to 22 days.
In summer the shortest period was 6 (lays, varying from 6 to 13 days. In the fall it varies from 9 to 13 (lays. The average period Fic.. .- Toxoptera muhlenbergi: throughout the season for the 13 individ- Eggs deposited in curled leafsheatL
uals of the series of first born is 13.1 (lays. Greatly enlarged. (Original.)
LENGTH OF LIFE OF THE VIVIPAROUS FORMS.

The length of life, like the period between birth and reproduction,
varies greatly. During the spring, when lower temperatures prevail, the viviparous forms will live from 30 to 63 days, while in the summer they live from 16 to 29 days, and in the fall over 30 (lays. The average lngth of life throughout the season for the 13 viviparous
individuals of the series of first born is 28.9 days.
THE SEXES.
The sexes make their appearance about the first week in October.
There does not appear to be any particular generation that consists






14 PAPERS ON APHIDID.E.

entirely of the sexes. A viviparous female may produce oviparous and viviparous females and males or she may produce only the sexes.
Males and females reach maturity in from 15 to 23 days. The female will not oviposit without having first been fertilized and will live, under these conditions, for about a month, her abdomen becoming greatly distended with eggs. A female with her abdomen thus distended was dissected after death and found to contain 7 eggs. If a male be placed in a cage with an oviparous female whenshe reaches maturity she will begin oviposition in about 4 days. The oviparous females, whether in the presence of males or not, apparently always maintain their normal position on the plant, never elevating the tips of their abdomens, as is the case with T. graminum.
PLACE OF OVIPOSITION.
When ready to oviposit, the females crawl down into the leaf sheath, which is usually separated from the plant stem for a part of its length and is somewhat curled, and deposit their eggs in this curled portion. The senior author has counted as many as 200 eggs in such a position. Figure 6 represents such a leaf sheath that has been uncurled FIG. 7.--ILamp-chimney molting cage used in rearing aphides. and photographed with
(Original.) the eggs in position. In
the fall of 1909 eggs were found by the thousands in just such situations.
FECUNDITY OF THE OVIPAROUS FEMALES. ,
The females of this species (do not appear to be quite so prolific as those of its near relative, the destructive "green hug." They produce




A NEW SPECIES OF TOXOI1TEIA. 115

MORTALITY OF EGGS.

For some cause (or (other the eggs appear never to hat'lch well. During the fall of 1908 from 50 to 100 eggs were c(llect(,d; awil in 1909 fully 1,000 were obtained, l)ut not a single egg hatchedl, though they were treated in the same manner as eggs of T. graminnvm and other species that stood the winter in good shape. During the sl)rin(g of 1910 eggs were found by the thousand in the o)pen fields with every evidence that not more than one-half to 1 per cent had hatched, though no unusual circumstances seemed in any way connected with them.

REARING METHODS.
As the Section
of Cereal and
Fo rage Insects
has been rearing
grass and grain
infesting aphides
for over four
yearsoutof doors
a brief summary
is given of the
methods employed, in the
hope that future
workers on these
nsects may find
some useful sug- FIG. 8.-Lamp-chimney gen- FIG. 9.-Lamp-chimney stock cage used in eration cage used in rearing rearing aphieds. Original.) gestions. aphides. -(Original.)
The rearing
stand (P1. I) consists ()f a shelf 2 feet wide of tongue-and-groove 1-inch boards, supported by a frame or base made of 2-inch by 4-inch material. These bases extend up above the shelf 20 inches and support a gable roof of lapped siding. The shelf is 2 feet from the ground. One side is closed by a hinged door that may be raised in case of a storm to prevent the cages fropn being blown over. This stand should be placed in the shade, preferably of trees, with the hinged side toward the direction from which the prevailing storms come. When it is not storming the hinged door should be let down to permit of free passage of air. It is also well to place a thermograph on the shelf with the cages in order that continuous temperature records may be secured.





16 PAPERS ON APHIDID.

The rearing cages used were of three kinds, a cage to observe molting (fug. 7), one for continuous-generation series (fig. 8). and a stock cage (fig. 9).
The cage for the molting observations (fig. 7) consists of a 5-inch flowerpot and the ordinary lantern globe, with a muslin cover over the top. A plant is potted, and a thin piece of black paper is fitted closely about the plant, the paper being the full size of the pot. Absorbent cotton is then pushed down about the plant to fill in completely the space between plant and paper; the cotton is then blackened with carbon ink. In this manner the grayish-white cast skins of the aphides can readily be seen against the black background.
The cage for the consecutive-generation series (fig. 8) is the same as the molting cage minus the paper.
The stock cage (fig. 9) consists of a 10-inch flowerpot and a 6-inch globe. This globe is the same as the one commonly used in villages for street lamps.
All pots should be placed in saucers and irrigated-never watered from the top, as this causes the soil to become very hard and the plants will not grow so well.
UNIVERSITY OF FLORIDA
HI HIlIIIIIIIIIIIIIH III lIH 11 IIIN 1111111

3 1262 09229 6515

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NyI