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Title: Florida Entomologist
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Creator: Florida Entomological Society
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Place of Publication: Winter Haven, Fla.
Publication Date: 1962
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Insects -- Florida -- Periodicals
Insects -- Periodicals
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The

FLORIDA ENTOMOLOGIST

Volume 45, No. 2 June, 1962



CONTENTS
Page

Muma, Martin H., and Harold A. Denmark-Intraspecific
Variation in Phytoseiidae (Acarina-Mesostigmata) -... 57

Philip, Cornelius B., and Calvin M. Jones-New North
American Tabanidae. XV. Additions to Records of
Chrysops in Florida -----------.....---.-.................... 67

Griffiths, James T.-Field Control with Zineb and Some
Other Compounds for the Control of Rust Mites on
Citrus in Florida ------------. ........... .................. 71

Hetrick, L. A.-Hatching of the Eggs of the Eastern Tent
Caterpillar, Malacosoma Americana (F.)
(Lepidoptera : Lasiocampidae) .-----.---..._ .._ ____-------...... 77

Peterson, Alvah-Some Eggs of Insects that Change Color
During Incubation -----.........---------------................ 81

Beck, Elisabeth C.-Five New Chironomidae (Diptera)
From Florida .....-----------........-... .......-- -... ... 889

Gouck, H. K., and Carroll N. Smith-The Effect of Age and
Time of Day on the Avidity of Aedes Aegypti --..........-- .. 93

Book Reviews --.. --------------------------...................................... 65, 96


Published by The Florida Entomological Society














THE FLORIDA ENTOMOLOGICAL SOCIETY


OFFICERS FOR 1961-1962

President ---....................................... ................-- -..........W C. Rhoades
Vice-President--.................-...................................... --------Henry True
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R. W. Baranowski
Other Members of Executive Committee John O'Neill
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INTRASPECIFIC VARIATION IN PHYTOSEIIDAE
(ACARINA-MESOSTIGMATA) 1

MARTIN H. MUMA2 AND HAROLD A. DENMARK 3

One of the more intriguing problems confronting the systematist is
intraspecific variation. The ability to distinguish, segregate or associate
individual specimens at the species level is largely dependent on the sta-
bility of the selected diagnostic characters. When stability is lacking, a
knowledge of the range of variability is essential to accurate work.
As mite studies have been intensified, it has become increasingly evident
that mites exhibit varying degrees of intraspecific variation. In some
groups a remarkable stability is found, in others variation seems to be the
norm. Interest in the problem is evidenced in discussions presented by
Goksu et al. (1960) on Trombiculidae, Newell (1958) on Trombidiidae,
Summers (1960) on Stigmaeidae, Wharton (1957) on parasitic Acarina and
Yunker (1955) on a species of Knemidokoptes.
In the family Phytoseiidae numerous variants have been reported. Sea-
sonal variation of Kampimodromus aberrans (Oud.) as evidenced by degree
of sclerotization and spinal length and serration was recorded by Chant
(1955). Variation of dorsal scutal reticulation on Amblyseius peregrinus
(Muma) was reported by Muma (1955). DeLeon (1957, 1958, 1959) re-
corded apparent variation in the number of lateral setae on Clavidromina
corn (DeLeon) and C. elliptical (DeLeon) caused by the occurrence of S2
on the dorsal scutum. In 1959 Chant stated "Phytoseiid mites show little
intraspecific variation and the criteria for specific separation, though ap-
pearing to be of minor importance, can usually be used with confidence,"
but in the same work he cited variation of diagnostic characters for Meta-
seiulus validus (Chant), Galendromus occidentalis (Nesbitt), Typhlodro-
mella rhenana (Oud.), Dubininellus macropilis (Banks) and D. bakeri
(Chant). While synonymizing T. kazachstanicus Wainstein with T. rhen-
ana (Oud.), Chant also stated that "Intra-specific variation accounts for
the few small differences that seem to be evident." Later Chant and Athias-
Henriot (1960) made a detailed presentation of character variation in spe-
cies of Phytoseius Ribaga and Dubininellus Wainstein. As yet, however,
no discussion of the systematic impact of such variations has been pre-
sented.
In this report we intend to demonstrate a wide range of variation in
diagnostic characters for two species of Phytoseiidae, Macroseius biscutatus
Chant, Denmark and Baker and Amblyseius peregrinus (Muma), to de-
scribe this range as it pertains to species segregation, and to discuss the im-
portance of a knowledge of such variation in the description of new species.
Descriptions of observed atypical or abnormal specimens of other species,
which may also be intraspecific variations, are also included.

1 Florida Agricultural Experiment Stations Journal Series No. 1323.
Contribution No. 4 Entomology Section, Division of Plant Industry.
2 Entomologist, University of Florida, Citrus Experiment Station, Lake
Alfred.
Chief Entomologist, Florida State Department of Agriculture, Division
of Plant Industry, Gainesville.










The Florida Entomologist


3





5




7





9





II




13


2





4





6


15





16


r~


Plate 1. Macroseius biscutatus Chant, Denmark and Baker. Figs. 1-16-
variations in the length of L1 and L2 and in the form of the anterior portion
of the anterior dorsal scutum on females. Figs. 17-22-variations in the
fragmentation of the male ventrianal scutum.


Vol. 45, No. 2


4J
(/V"2, 2^












Muma: Intraspecific Variation in Phytoseiidae 59

All specimens referred to in this study were collected from their natural
habitats and examined under a phase-contrast microscope.

Macroseius biscutatus Chant, Denmark and Baker
Figures 1 to 22

The subfamily Macroseiinae and genus Macroseius were erected by
Chant, Denmark and Baker (1959) for this phytoseiid mite because it has
two dorsal scuta. A diagnosis and redescription of the species is given so
that intraspecific variations can better be presented and discussed. The
modified Garman system as presented by Muma (1961) is used for setal
designation.
DIAGNOSIS: This distinctive species is readily recognized by its large
size, divided dorsal scutum, and the presence of seven pairs of dorsal (D)
setae. The species seems to have affinities with both the Digamasellidae
and Phytoseiidae of which it may well be a primitive link. It is retained
in the latter family for the present.
FEMALES: Length, D1 to D7, of twenty randomly selected specimens
470.8 to 577.8/, anterior dorsal scutum 226.4 to 283.0,a wide, posterior dor-
sal scutum 267.0 to 328.1, wide. The modal length is 533.6/ and modal
widths 248.2 and 301.01 respectively. Dorsum covered with two variable
subequal scuta, anterior and posterior, with the suture between D4 and Ds.
Anterior scutum with 10 pairs of setae, posterior median areas slightly
imbricate. Setae L1 and Le minute to large and variable in comparison to
each other. Setae L3, L4 and S1 long, smooth and thick. Setae Dz, Ds, D4
and M1 minute.
Entire posterior dorsal scutum slightly imbricate, with 9 pairs of setae.
Setae L5 long, smooth and thick; La and Ms long, serrate and thick. Setae
D5, D6, D,, Ms and L, minute. Seta S2 on interscutal membrane.
Spermathecae with cervix bell-shaped. Sternal scutum slightly longer
than wide with 3 pairs of setae. Metasternal scuta elongate, each with a
seta. Genital scutum truncate posteriorly, longer than wide, with 1 pair
of setae. Two pairs of metapodal scuta. Ventrianal scutum approximately
triangular with 1 pair of preanal setae.
Fixed digit of chelicerae with 12 to 15 teeth and pilis dentilis; movable
digit with 2 or 3 large teeth. Leg IV with 3 macrosetae (genu, tibia and
basitarsus).
MALES: Length, D1 to D,, of 10 randomly selected specimens 291.6 to
538.4A, anterior dorsal scutum 274.4 to 325.9/ wide, posterior dorsal scutum
240.1 to 298.4p wide. The modal length is 445.9A and the modal widths
284.71 and 260.7, respectively. Dorsum as in female except seta S2 on
anterior dorsal scutum. Ventrianal scutum separated from sternitigenital
scutum, fragmented and with 4 pairs of preanal setae. Fragmentation
variable, often resulting in two major and one or more minor scuta. Cheli-
cera' with spur-shaped spermatophore bearer. Leg IV with macrosetae as
in female.
Variations: In the original description L, is given as slightly longer
than L,. This diagnostic character is highly variable as illustrated in
Figures 1-16. One hundred females were randomly selected and L, and L2
measured to establish the ratio of L1/La. The ratio ranged from 0.27 to












The Florida Entomologist


3.45p with 77 per cent of the specimens having L1 shorter than L2. As
shown in Figures 1-16 the lengths and ratios may vary between the right
and left side of the same specimen. A lesser number of males were ob-
served and also found to have a high degree of variation in the lengths
and comparative lengths of L1 and La.
The anterior dorsal scutum is highly variable. A spur may or may not
be present at the junction of the peritremal scutum and anterior dorsal
scutum as shown in Figures 1-16. Figures 14 and 15 show other occasional
variations in the shape of the anterior dorsal scutum.
The male ventrianal scutum is fragmented into two large variable scuta
with an occasional third and fourth smaller scutum present as shown in
Figures 17 to 22. One of the 4 pairs of preanal setae is sometimes found
on the membrane between the two larger fragments as in Figure 18.

Amblyseius peregrinus (Muma)
Figures 23 to 31

In order to fix the identity of this species prior to an examination of
intraspecific variation, the following diagnosis and redescription of the
species is presented.
DIAGNOSIS: This is the typical species of the subgenus Typhlodromalus
Muma and is closely related to A. newsami (Evans), A. africanus (Evans),
A. mesembrinus (Dean), A. scutalis (Athias-Henriot) and A. planetarius
(DeLeon) from which it differs in having M serrated and much longer than
L, and L,. Other near relatives include A. jucundus (Chant), A. robiniae
(Chant), A. evansi (Chant) and A. primulae (Chant). Of these species,
A. jucundus is distinctive by the three long macrosetae on Leg IV. The
remaining three species, however, seem to possess no distinguishing char-
acters that cannot be demonstrated to fall within the range of variation of
A. peregrinus.
FEMALES: Dorsal scutum of twenty randomly selected specimens 330
to 385u, long and 210 to 235M wide, with the modal length 365t and the
modal width 225/. Scutum faintly to strongly reticulate.
Dorsal setae except for D1 small to minute; D1 slightly to distinctly
larger than other dorsals. M1 and M2 small; Ms two to four times longer
than other medians and distinctly serrate. Lateral setae Li, L4 and La
distinctly longer than other laterals with Li shortest; Ls distinctly serrate.
Lateral setae L2, Ls, L5, L6 and L, small with L, smallest; L2 slightly to
distinctly smaller than La; Le slightly to distinctly larger than L,. S, and S2
small to minute.
Fixed digit of chelicerae with 8 to 10 teeth and pilis dentilis; movable
digit with 3 to 4 teeth. Sternal scutum distinctly longer than wide, smooth
and lobate posteriorly. Ventrianal scutum elongate, constricted laterally
and smooth; preanal setae arranged in anteriomarginal triangles; preanal
pores elliptical and nearer posterior preanal setae than each other.
Macrosetae on Leg IV short, that on tarsus longest, that on tibia short-
est; genual and tarsal macrosetae not to distinctly knobbed.
Spermathecae with cervix cup-shaped internally, abruptly narrowed
into an elongate, slender tube which terminates in a knobbed atrium.
MALES: Dorsal scutum of twenty randomly selected specimens 235 to


Vol. 45, No. 2









Muma: Intraspecific Variation in Phytoseiidae


300/ long and 150 to 180/ wide with the modal length 265/~ and the modal
width 150t.
Scutum and station of scutum as in females except the scapular setae
occur on the scutum.
Ventrianal scutum roughly triangular and reticulate with three pairs
of preanal setae and a pair of elliptical preanal pores.
Macrosetae as in females except they are not knobbed.


1.3- 1.7






S23


1.6-2.0






S26


2 .- i.6






24


1,6-1.7



'1


1.5-1.5






25


1.4-2.0






28


Plate 2. Amblyseius peregrinus (Muma). Figs. 23-28-variations in
the ratios of M2/L5 and Ms/L6 on females. Figs. 29-31-variations in the
female ventrianal scutum.
Spermatophore bearer provided with a broad lobate lip, an opposing
short acute spur and a slight constriction just behind these apical proc-
esses.
Variations: Because of the wide range in size, setal lengths and host
plants of the above described specimens, there was some doubt as to the
conspecificity of the material. In order to determine homogeneity or hetero-
geneity of this randomly selected sample, 100 mounted females, including
the above described specimens, were examined and the lengths and ratios












The Florida Entomologist


99.9L


0 =M. /LS

SM3/ Lg


*C


0 .11 I I I 1 I I I I I
I 1.1 1.3 1.5 1.7 2
Logarithms of Ratios
Graph 1. Relationships of the logarithms of the accumulated frequen-
cies and ratios of M2/L and M3/L8 in a randomly selected series of 100
specimens of Amblyseius peregrinus (Muma).

of M2/Ls, and Ms/L8 were obtained. When the resulting logarithms of the
ratios and logarithms of accumulated frequencies of the ratios were com-
puted and plotted against each other, two straight line relationships were
obtained. These are shown in Graph 1. They indicate that as far as com-
parative lengths of these setae are concerned, the specimens examined were
from the same population and conspecific. Intersection of the two graph
lines indicates a high degree of variation in the combination of the ratios
of M2/L5 and Ma/Ls from specimen to specimen. Figures 23 to 28 give
several examples that include maximum, minimum and modal lengths of
the 4 setae. Although the comparative relationships of the above cited
setae were the only ones treated numerically, variations in many other char-
acters were studied. Most striking were those dealing with ventrianal
scuta, macrosetae of Leg IV and comparative sizes of L, and LT. Ventri-
anal scuta varied from the robiniae type through the peregrinus type to the
primulae type as shown in Figures 29 to 31. Macrosetae varied from acutely


Vol. 45, No. 2













Muma: Intraspecific Variation in Phytoseiidae 63

pointed to broadly knobbed. Setae L6 varied from slightly longer than L7
to nearly three times as long.
Other variations noted were the occasional loss of the right or left
D2 or D4, the occasional occurrence of three D4s and in one case a malformed
ventrianal scutum, horn-shaped on the right side with four pairs of preanal
setae but normal on the left side.

MISCELLANEOUS SPECIES

Observations on varying numbers of specimens of other species indicate
variation in characters usually cited as diagnostic. A few of these are
cited below.
In a long series of Amblyseius limonicus Garman and McGregor from
Florida, Ms was smaller than Le and L, on most specimens but larger on a
few; Le was commonly equal to L, in size but distinctly larger on some;
D1 usually was distinctly smaller than L1, but on several specimens was
sub-equal; the ventrianal shield was usually vase-shaped but occasionally
was nearly parallel-sided.
Ten specimens of A. mesembrinus (Dean) from Mexico have L6 equal to
L7 except on two specimens on which L7 was distinctly larger; the ventrianal
scutum was broad posteriorly and narrow anteriorly with concave sides on
most specimens but vase-shaped on two; most specimens had the anterior
end of the ventrianal scutum irregular, so much so on one specimen that
only two preanal setae occurred on one side of the scutum.
Among 15 specimens of Galendromus annectens (DeLeon) from Florida,
two had only three preanal setae on the left side of the ventrianal scutum.
The presence of three and/or four preanal setae on the ventrianal scutum
was a common occurrence on 10 specimens of G. occidentalis (Nesbitt) from
California. On the other hand, examination of more than 50 specimens
of G. floridanus (Muma) revealed no variation in the number of preanal
setae. On one specimen of G. floridanus, one Di was missing.

DISCUSSION

The demonstration of a wide range of variability in the lengths and
comparative lengths of L1 and L, on M. biscutatus indicates the unreliability
of these characters in this genus and species. Primitive genera and species
in the Amblyseiinae should be investigated carefully for a similar varia-
tion before too many additional species are described. Suspect genera in-
clude Phytoseiulus Evans, Proprioseius Chant and Amblyseiulus Muma.
Although form of the dorsal scutum is seldom cited as diagnostic, most
workers accurately figure and describe seemingly intraspecific variations
of this structure. The observed intraspecific variation of the anterior dor-
sal scutum on M. biscutatus suggests that such may exist in other species.
If so, detailed description of the character may be superfluous, unless the
range can be described. Diagnoses and keys should be based on static char-
acters or describe ranges of variations.
Muma (1961) expressed doubt that a fragmented male ventrianal scutum
was a valid criterion for generic separation. Variation of this structure
in M. biscutatus from partly fragmented in the allotype to variously frag-
mented in other specimens indicates that the character may be of minor













64 The Florida Entomologist Vol. 45, No. 2

importance even in specific segregation. Applications of this knowledge
are important in dealing with highly sclerotized Amblyseiines and species
of Typhloseiopsis DeLeon.
A wide range of intraspecific variation of diagnostic characters appar-
ently exists within the large heterogenous genus Amblyseius Berlese. Ex-
amination of A. peregrinus (Muma) has revealed such a variation that it
may be necessary to synonymize the names A. robiniae (Chant), A. evansi
(Chant) and A. primulae (Chant). Furthermore, the range in lengths
and comparative lengths of lateral and median setae seems to invalidate
precise setal lengths and comparative lengths as diagnostic characters.
Also, the description of precise ventrianal and macrosetal form for species
recognition is of doubtful value. When setal variation is observed, numeri-
cal description should be used to indicate the range of variation. All spe-
cies of Amblyseius and possibly those of Amblyseiulus and Cydnodromus
Muma should be tested mathematically.
Preliminary investigation of other species of Phytoseiidae has revealed
a wide range of intraspecific variation in some forms and practically none
in others. It would seem that each species should be studied to determine
its inherent range of intraspecific variation. Until such is done, at least
for the common or important forms, species descriptions based upon minor
questionable diagnostic characters should be dealt with cautiously.

LITERATURE CITED
Chant, D. A. 1955. Notes on mites of the genus Typholdromus Scheuten,
1857 (Acarina: Laelaptidae) with descriptions of the males of some
species and the female of a new species. Canad. Ent. 87 (11): 496-
503.
Chant, D. A. 1959. Phytoseiid mites. Part II. A taxonomic review of
the family Phytoseiidae with descriptions of 38 new species. Canad.
Ent. 91, Suppl. 12: 45-166.
Chant, D. A., and C. Athias-Henriot. 1960. The genus Phytoseius Ribaga,
1902 (Acarina: Phytoseiidae). Entomophaga 5 (3): 214-228.
Chant, D. A., H. A. Denmark, and E. W. Baker. 1959. A new subfamily,
Macroseiinae Nov. of the family Phytoseiidae (Acarina: Gamasina).
Canad. Ent. 91 (12): 808-811.
DeLeon, Donald. 1957. Three new Typhlodromus from Southern Florida
(Acarina: Phytoseiidae). Fla. Ent. 40 (4): 141-144.
DeLeon, Donald. 1958. Four new Typhlodromus from Southern Florida
(Acarina: Phytoseiidae). Fla. Ent. 41 (2): 73-76.
DeLeon, Donald. 1959. The genus Typhlodromus in Mexico (Acarina:
Phytoseiidae). Fla. Ent. 42 (3): 123-129.
Goksu, K., G. W. Wharton, and C. E. Yunker. 1960. Variations in popu-
lations of laboratory-reared Trombicula (Leptotrombidium) akamu-
ski (Acarina: Trombiculidae). Acarologia, Tome II, fasc. 2: 199-209.
Muma, Martin H. 1955. Phytoseiidae (Acarina) associated with citrus
in Florida. Ann. Ent. Soc. Amer. 48 (4): 262-272.
Muma, Martin H. 1961. Subfamilies, genera and species of Phytoseiidae
(Acarina: Mesostigmata). Bull. Fla. St. Mus., Biol. Sci. 5 (7):
267-302.












Muma: Intraspecific Variation in Phytoseiidae


Newell, Irwin M. 1958. Specific characters and character variants in
adults and larvae of the genus Paratrombium Bruyant 1910 (Acari,
Trombidiidae) with descriptions of two new species from western
North America. Pacif. Sci. 12: 350-370.
Summers, F. M. 1960. Several Stigmaeid mites formerly in Mediolata
redescribed in Zetzellia Ouds. and Agistemus new genus (Acarina).
Proc. Ent. Soc. Wash. 62 (4): 233-247.
Wharton, G. W. 1957. Intraspecific variation in the parasitic acarina.
Syst. Zoo. 6 (1): 24-28.
Yunker, Conrad E. 1955. Apparent extrinsic variation in Knemidokoptes
piliae Lavoipierre and Griffiths, 1951 (Acarina: Sarcoptiformes).
Jour. Parasit. 41 (6): 642-643.




THE BEETLES OF THE UNITED STATES (A MANUAL FOR IDENTIFICATION), by
Ross Arnett, Jr. The Catholic University of America Press, Washington,
D.C. Part I, Fascicles 1-9, xi+210 pp., 196 fig., 1960; Part II, Fascicles
10-25, 158 pp., 101 fig., 1961; Parts III-VIII to be published by late 1962.
Completed manual $25.00, optional loose-leaf binder $3.95; sections also
priced separately based on number of pages.
Anyone interested in the study of United States beetles will find this
book to be "the one indispensable reference". Certainly it will assume a
most prominent position on the library shelves of every professional coleop-
terist, along with other classical treatises. We anxiously await the parts
to be published since several of the larger families have not yet been treated.
No publication during the past 30 years will have such a profound desir-
able effect on the study of beetles in the United States!
The author states in the introduction that this is an up-to-date version of
Bradley's A Manual of the Genera of Beetles of America, North of Mex-
ico, with a completely revised form. He is conservative in his appraisal
of his own work because this book certainly surpasses any similar works
on U. S. beetles. Since our latest catalogue of beetles has had five supple-
ments, the last of which was issued 14 years ago, there is no current com-
prehensive reference on the U. S. beetle fauna. With this treatise, includ-
ing its extremely useful references, we can once again feel nearly "up-to-
date" at the generic level.
In contrast to the Dillon book reviewed later, this book treats the genera
of the U. S. (occasionally keys to species are also given for some of the
smaller families). The latest keys to species are cited after each genus thus
eliminating an extensive search of the literature. From the professional
standpoint, this one advantage is well worth the price of the book.
It is printed on good quality 6x9 looseleaf paper to fit an optional three-
post binder. Although the paper quality is good, it is very thin, which
causes pages to tear out of the binder easily and makes turning of indi-
vidual pages clumsy. The format of the book is an innovation which should
be more widely used. Each family is treated as a separate fascicle with
individual as well as continuous pagination. Each fascicle has its own
index and bibliography, all of which contributes to the flexibility of this
(Continued on Page 95)
















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NEW NORTH AMERICAN TABANIDAE. XV. ADDITIONS
TO RECORDS OF CHRYSOPS IN FLORIDA

CORNELIUS B. PHILIP1 AND CALVIN M. JONES2

Reported here are two remarkable additions to the tabanid fauna of
Florida, a state supposedly well surveyed for this family, as documented
in the lists of Fairchild (1937), Bargren (1961), and Jones and Anthony
(1962). Both species have probably escaped notice heretofore because they
are strongly precinctive or have peculiar habits. The new species described
below was taken while attacking horses and is named for the collector.
The other, the bog-dwelling Chrysops hyalinus, has not been reported to
show any interest in parasitism, though, females, like all others of the
genus, almost certainly require some kind of vertebrate blood to mature
their eggs.
Chrysops tidwelli, n.sp.
Figure 1
A small, dark species, including scutellum, with abdomen contrasting
yellow on 2 basal segments, callosity yellow on disc, brown on upper mar-
gin, femora yellow, and wing picture sharply black in 1st basal cell and
through discal cell to hind margin in cell Ma, cubital cell hyaline, apical
spot widened to include nearly all of cell R4, a spur in R5, hyaline triangle
sharply acuminate before reaching vein Rz,+ and widely open behind.
HOLOTYPE: Female, 6 mm. Eye pattern (relaxed) most nearly approach-
ing C. bistellata Daecke (1906, fig. 30) with the occipital border contiguous
to the margin, the other spots separated vertically from one another and
from the anterior eye margin, and the arrowhead unusually vertically ex-
tended and isolated. Frons blue-gray pollinose, taller than broad, a large,
quadrate black shining spot surrounding the ocelli at vertex, and narrowly
connected beneath to the ovoid, yellow and blackish-brown callosity. Face
entirely yellow, bare except for narrow incomplete lateral pollinose stripes,
tubercles normal. Antennae slender, the 2 basal segments and extreme
base of flagellum yellowish, darkening to black beyond. Palpi reddish.
Notum and scutellum blackish with a wide plumbeus stripe anteriorly.
Pleura dark with 2 wide yellow stripes. Legs entirely yellow except dark
distad of the middle of anterior tibiae.
Abdomen bicolored above and below, yellow on basal 2 segments ex-
cept for inconspicuous midventral darkening; remainder blackish, the an-
terior half of tergite 3 notched with 3 dull reddish spots and similar spots
laterally on sternite 3.
Escambia County, Florida, 9 Aug., 1960. M. Tidwell. In U. S. National
Museum (USNM).
Paratype females, 12 same data or 7 August. Dried blood-meals evi-
dent in two. In close agreement with type, though occasionally the callosity

SU. S. Department of Health, Education, and Welfare, Public Health
Service, National Institutes of Health, National Institute of Allergy and
Infectious Diseases, Rocky Mountain Laboratory, Hamilton, Montana.
2 Entomology Research Division, Agricultural Research Service, U. S.
Department of Agriculture, Lincoln, Nebraska.












The Florida Entomologist


and segment 3 of the abdomen may be almost entirely black or the dark
spur in cell Rs is missing. In USNM, Florida State Department of Agri-
culture, and collections of the authors and L. L. Pechuman.
This interesting little species must be very localized to have remained
this long undetected in a well surveyed state. In Philip (1955), it runs to
couplet 75 of the key to females, where it quickly separates from C. hinei
Daecke and C. beameri Bren. by nonstriate abdomen, dark scutellum, en-
tirely yellow hind femora, and apex of hyaline triangle not reaching vein
&.s:. The wing picture is somewhat like that of C. obsoletus Wied. and
C. dacne Phil. but the bicolored abdomen and peculiar eye pattern again
are distinctive in this new species.

























Figure 1. Chrysops tidwelli new species. Head (frontal and lateral
views showing eye pattern, relaxed, and antenna) and wing pattern.

Notes from the collector describe the circumstances as follows: Taken
7 miles southwest of Cantonment (Escambia County). The terrain was
gently rolling. Vegetation consisted of various pines and wire grass on
the elevated portions, while the lower portions consisted of predominantly
bay trees and other lowland vegetation. A small stream drained the area
and was approximately 100 yards from where the specimens were taken.
The collections were made from a horse between 3 and 6 p.m. on clear,
sunny days.
Chrysops (Liochrysops) hyalinus Shannon
The species has not been reported for many years and there was con-
cern that "civilization" of the only two known bog localities of its occur-
rence near Beltsville, Md., and Southern Pines, N. C., might have resulted
in its disappearance following the "universal urge of human beings to drain


Vol. 45, No. 2












Philip: New North American Tabanidae


swamps" as Philip Wylie puts it (1961). It was a pleasure, therefore, to
receive a nice series of 10 females from Dr. Howard V. Weems, taken by
E. W. Holder, Jr., in April, 1960, at Glen St. Mary near the southern border
of the great Okeefenokee Swamp. This is a new Florida record and affords
the opportunity, it is hoped, of capturing the unknown male of this unique
little species with such peculiar habits and characteristics that it was as-
signed by Philip (1955) to a new subgenus.

Tabanus aranti Hays
This is a species of Tabanus which is also likely to be added to the
Florida list.
A female of this recently described, large, black species (Hays, 1961)
from Alabama is in the collection of one of us (CBP) and was taken con-
siderably south of the original Auburn series. The specimen was collected
by L. S. Henderson at Florala (Covington County), Alabama, 1 June, 1939,
which places it practically on the northern Florida boundary. The species
certainly occurs in Florida also.

LITERATURE CITED
Bargren, William C. 1961. An annotaed list of horse flies of Florida and
an illustrated key to the genera (Diptera: Tabanidae). Fla. Ent.,
44: 69-84.
Fairchild, G. B. 1937. A preliminary list of the Tabanidae (Diptera) of
Florida. Fla. Ent. 19: 58-63; 20: 10-11.
Daecke, E. 1906. On the eye-coloration of the genus Chrysops. Ent.
News, 17: 39-42.
Hays, K. L. 1961. Tabanus aranti sp. nov. (Diptera, Tabanidae) from
Alabama. Ent. News, 72: 127-129.
Jones, C., and D. W. Anthony. 1962. The Tabanidae (Diptera) of Florida.
U. S. Dept. Agric. Tech. Bull. (in press).
Philip, C. B. 1955. New North American Tabanidae. IX. Notes on and
keys to the genus Chrysops Meigen. Rev. Brasil. Ent., 3: 47-128.
Wylie, Philip. 1961. Why are they spoiling Florida? Sat. Eve. Post,
Dec. 23, 1961, pp. 8, 10.












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VC iAIA M D














FIELD CONTROL WITH ZINEB AND SOME OTHER
COMPOUNDS FOR THE CONTROL OF RUST
MITES ON CITRUS IN FLORIDA 1

JAMES T. GRIFFITHS 2

Fisher (1956) first found that zineb controlled russetting on citrus in
Florida. As a result small amounts of zineb were used commercially in
19,57, and since that time zineb has been generally the miticide of choice
for control of citrus rust mite, Phyllocoptruta, oleivora (Ash.). Johnson
et al (1957) reported on the use of zineb in more detail. They showed that
chlorob-nzilate was also quite effective, but nabam (sodium ethylene bis-
dithiocarbamate) and nabam plus zinc sulfate were found to be markedly
inferior as compared with zineb. They also stated "although no variation
in thoroughness of application was attempted, it is believed that thorough
coverage of all fruit and leaf surfaces are needed for optimum rust mite
control with zineb."
Johnson (1960) reported that copper reduced the efficacy of zineb and
he again recommended thorough applications. As a result of continued
work, he reported in 1961 that a combination using chlorobenzilate at post-
bloom time, zineb in the summer, and wettable sulfur in the fall of the
year was a satisfactory program for citrus rust mite control.
Griffiths (1960) discussed the use of zineb in a commercial grove opera-
tion during 1958 and 1959. He concluded that zineb in combination with
copper was not as effective as zineb alone and that where severe infesta-
tions occurred at the time of application, the efficacy of zineb was materially
reduced. Under these circumstances, increasing the zineb appeared to im-
prove results.
During the five years, 1957 through 1961, that zineb has been in use
as a miticide on Florida citrus, materially different results have been ob-
tained during the last two years as compared with the first three. Between
1957 and 1959 rust-mite control following zineb applications was almost
spectacular. In many instances sprays applied in June or July resulted in
extremely low rust-mite populations throughout the remainder of the sum-
mer and fall and even until the' post-bloom application was made the fol-
lowing spring. During the summer of 1960 an entirely different situation
arose. In many cases rust-mite control lasted only 30-60 days. Rust-mite
control was difficult throughout the winter of 1960-61 and populations were
extremely high during the spring of 1961. Both spring and summer appli-
cations of zineb in 1961 were often ineffective.
The data presented here were obtained in an effort to determine the
comparative effectiveness of wettable zineb (zinc ethylene bis-dithiocarba-
mate) and a tank-mix of the diammonium salt reacted with zinc sulfate;
to test the necessity for thorough coverage when zineb was used; and to
find some basis for an explanation of the inferior control obtained with
zineb in 1960 and 1961.

SPresented at the Entomological Society of America annual meeting in
Miami, November, 1961.
2 General Manager, Eloise Groves Association, Winter Haven, Florida.












The Florida Entomologist


Eloise Groves Association has under its control approximately 7,000
acres of citrus grove. Since 1958 this acreage has been almost exclusively
on zineb as a miticide for rust-mite control. Since other workers had not
reported on tests with the ammonium salt of ethylene bis-dithiocarbamate,
it was decided in the fall of 1960 to compare the effectiveness of zineb as
a wettable powder with a tank-mix material, zimix3. Theoretically, zimix
should be chemically identical with zineb. A pint of the zimix contains the
equivalent in active ingredient of a pound of 65% wettable zineb. How-
ever, in the tests reported here, a pint of zimix was compared with a pound
of 75% wettable zineb.
Experimental plots were initially set up in two blocks; one composed
of pink Marsh seedless grapefruit, approximately 20 years of age; and
the other of Parson Brown oranges of approximately 35 years of age. The
trees were comparable in size and similar dosages were used in both blocks.
Miticide treatments were duplicated in the oranges and triplicated in the
grapefruit.
The first experiment was applied on October 3, 1960. All materials
were applied with a power sprayer which was driven at two speeds, 11/4 and
2 miles per hour. All miticides were applied as concentrates and were
tested on the basis of a given amount of material per row across a 40 acre
block. A row was equivalent to approximately 0.9 of an acre. In this
experiment, zineb was applied at 5 pounds per row at 1% and 2 mph
and at 10 pounds per row at 2 mph. Five and 10 pints of zimix were
applied at the same speeds. Immediate kill was effected in all plots.
After six months, populations were still lower than 5% in all plots. No
differences occurred due to source of material, dosage, or speed of appli-
cation.
The next test was made between April 5 and 14, 1961 in the same blocks.
The results are shown in Table 1. Copper which is often applied at the
post-bloom time was included in this experiment at the rate of six pounds
of tribasic copper per row. In addition, on the grapefruit only, four pounds
of lead arsenate was applied per row for early maturity. All sprays were
applied by a sprayer at 21/ mph. Zineb was used at 5, 71/, and 10 pounds
of material per row and was compared with 5, 7 and 10 pints of zimix
per row. This afforded an opportunity to determine if increased amounts
of miticide resulted in improved rust mite control when copper was in-
cluded in the spray mixture.
On June 2nd rust mite infestations in the plots in the orange grove
averaged about 25%. There were no differences between amount or source
of material. Ordinarily in June, infestations of this magnitude should be
sprayed. This was done on June 17th.
In the grapefruit, control was effective until after June 30th. At that
time there were no differences between treatments, but the summer scali-
cide was applied routinely as noted below.
The third experiment was performed on June 17th in the orange block
only and included a comparison between 5, 7 and 10 pounds or pints of
miticide. Two weeks had elapsed since the last rust mite count and it is
possible that the population had increased considerably in the interim.

Zimix is a trade name for diammonium ethylene bis-dithiocarbamate re-
acted in the spray tank with zinc sulfate to form the zinc salt.


Vol. 45, No. 2












Griffiths: Control of Rust Mites on Citrus in Florida 73

Approximately a month later on July 25th, populations averaged 44%
where zineb had been applied and 41% where zimix was used. Once again
there was no difference between the dosage or material. All were ineffec-
tive.

TABLE 1.-COMPARISON OF THREE LEVELS OF ZINEB AND ZIMIX IN
COMBINATION WITH COPPER APPLIED BETWEEN APRIL 5 AND 14, 1961

% Infestation in Orange % Infestation in
Miticide Plots Grapefruit Plots
Miticide
Miticide Per Row Pre Pre-
Spray May 9 June 2 spray June 2 June 30

5 lbs. 20 23 25 0 3 20
Zineb 7 lbs. 40 43 28 3 3 12
10 lbs. 2 8 32 0 3 10
Avg. % Infestation 31 25 28 1 3 14

5 pts. 20 25 22 3 3 9
Zimix 72 pts. 17 35 23 0 3 6
10 pts. 8 8 25 0 0 9
Avg. % Infestation 15 23 23 1 2 8


Another spray application was made on the grapefruit plots on July
4th. Zineb and zimix were used at 5, 7/2 and 10 pounds or pints per row.
Copper, oil and parathion were included in all sprays. After only 50 days,
the zineb plots averaged 64% infestation and the zimix 42%. As in the
post-bloom application when copper was used, increasing the amount of
miticide did not improve rust-mite control.
On July 26, the oranges were resprayed with the same materials that
had been used in the July 4 spray on grapefruit except that no oil was in-
cluded in the spray. After only 30 days the zineb plots averaged 23%
and the zimix 47% and respraying was necessary. As in the grapefruit
plots, increasing the miticide did not improve control.
By August 1961, it was obvious that the use of zineb in June and July
scalicide sprays in commercial groves had not resulted in satisfactory rust
mite control. As a result chlorobenzilate was included in subsequent tests
with zimix and zineb.
Table 2 shows the results from the experiment which was applied on
August 31 in the above mentioned blocks. Chlorobenzilate was included
at the rate of 1 quart per row and was applied at 1%/4 and 2/2 mph. Zineb
and zimix were used at 7/2 pounds and 71/2 pints per row, respectively,
and were also compared at 114 and 21 mph. In the grapefruit plots, only
three weeks after spraying, on September 21st, rust mites were still so
prevalent in the zineb sprayed plots that it was necessary to respray these.
In view of the fact that populations were somewhat higher in the zineb
plots at the time that the spray was applied, it is highly questionable that
any conclusions should be drawn. On November 10, all other treatments
were still satisfactory in both blocks. Speed of application did not appear
to be a factor in control.












The Florida Entomologist


TABLE 2.-A COMPARISON OF CHLOROBENZILATE AND ZINEB, AND ZIMIX
WHEN APPLIED AT TWO DIFFERENT RATES OF SPEED ON ORANGES
AND GRAPEFRUIT ON AUGUST 31, 1961

% Infestation
in Orange % Infestation in
Miticide Plots Grapefruit Plots
Miticide Per Speed of
Row Sprayer Pre Nov. Pre Sept. Nov.
Spray 10 Spray 21 2

1 qt. 11 mph 22 0 68 4 0
Chloroben-
zilate 1 qt. 21/2 48 0 53 3 0
Avg. % Infestation 35 0 61 4 0

712 Ibs. 11 mph 70 58* -
Zineb
712 lbs. 212 18 5 .53 46* -
Avg. % Infestation 18 5 62 52 -

72 pts. 11/ mph 40 0 44 16 3
Zimix
72 pts. 21/2 40 5 28 20 17
Avg. % Infestation 40 3 36 18 10

* Required respraying at this time.

Another experiment was conducted in a block of 14 year old Jaffa
oranges. Experimental sprays were applied by Sprayer at 21 mph on
September 5th, 1961. Three treatments were compared: six pints of zimix
per row; two pints of zimix and one pint of chlorobenzilate per row; and
1% pints of chlorobenzilate per row. Infestations averaged about 75%
at the time of application. Plots were replicated four times. By October
17 the plots averaged infestations of 15%, 5% and 212% respectively. On
November 20 the averages were 27, 17, and 24% respectively, and the in-
festations was found primarily at the north end of all plots and appeared
to be a function of location rather than treatment.

DISCUSSION

Griffiths (1960) had previously suggested where heavy rust-mite infes-
tations were found, that by increasing the zineb by 50 to 100% more ef-
fective control was attained. Similarly he suggested that by increasing
the amount of zineb when copper was used, more satisfactory control re-
sulted. This was especially true during the 1958-59 seasons but during
1961, these conclusions were not substantiated. Field usage in 1960 and
1961 strongly suggests that a material such as chlorobenzilate offers much
more effective control during the spring and summer months than does
zineb if copper is to be used in the spray or if high rust mite infestations
are present.


Vol. 45, No. 2












Grifiths: Control of Rust Mites on Citrus in Florida 75

The difference in rust-mite control between the 1957-59 and 1960-61 sea-
sons naturally gives rise to speculation that the continued use of zineb has
resulted in the development of resistance on the part of the citrus rust-mite
population. Although this conclusion cannot be positively discounted, there
is a considerable body of evidence which suggests that the differences in
control have been the result of population differences rather than resistance
to miticides.
Examination of population trends in sprayed groves, using a scheme
developed by Dr. W. A. Simanton of the Florida Citrus Experiment Station,
indicated that rust-mite populations have behaved in a different manner
when the years 1960-61 are compared with 1957-59.
In the three years, 1957-59, rust-mite populations peaked sharply at
the end of July. This peak was followed by a rapid population decrease.
During the 1960-1961 seasons, there was no sharp population increase dur-
ing July, but rather a prolonged period of relatively high population through-
out the summer. Exactly how this has affected rust-mite control with zineb
is at present unknown, but it is probable that it is a major factor in the
difference in the degree of effectiveness of zineb. A careful study of rust-
mite population trends in unsprayed groves might offer a satisfactory
answer to the diametrically opposed results when 1957-59 is compared with
1960-61.
Field data do not appear to justify a conclusion that resistance is a
problem. There are numerous groves under the care of the author which
have been sprayed regularly with zineb for four years and which had ex-
cellent results with zineb during 1961. The data reported here indicate
that in some plots where zineb has been in continuous use for several years
prior to the initiation of these experiments, and where zineb was a failure
during the spring and summer months, its application in September or in
late August was a complete success. This control is certainly suggestive
that resistance was not the problem, and that some other factor was re-
sponsible.
The use of the tank-mix material, zimix, was suggested because it could
be sold on a more economical basis than could zineb wettable powder. As
noted above, Johnson et al (1957) reported that when the sodium salt was
used results were unsatisfactory, but he did not report on the use of the
ammonium salt. Results here are certainly indicative that zimix as used
in these experiments was as satisfactory, or in some cases as ineffective,
as was zineb. It would appear that the two were interchangeable and that
cost or convenience of use would be the deciding factor rather than the
source of material. This has been essentially true in the grove operations
under the author's supervision where a considerable amount of zimix was
used during the 1961 season, and it was certainly as effective as was zineb
wettable powder.
CONCLUSIONS

On the basis of field observations as well as specific experiments re-
ported here, it is concluded that rust-mite control in Florida citrus groves
followed different patterns in 1960-61 than in 1957, 1958 and 1959. This
was evidenced by the fact that rust-mite populations were not as effectively
controlled as during the preceding three years.












The Florida Entomologist


Zineb (ethylene bis-dithiocarbamate) wettable powder and zimix (diam-
monium ethylene bis-dithiocarbamate plus zinc sulfate reacted in the spray
tank) were found to be equally effective for rust mite control. Although
an increase in dosage had shown improved control when applied either with
copper or on severe infestations in the past, during the summer of 1961
such improvement was not evident.
Varying the speed of application by a power sprayer from 11/4 to 21/
mph did not have any effect on rust-mite control.
During the summer of 1961, field results indicated that chlorobenzilate
was perhaps more effective than zineb. This was particularly true where
heavy infestations of rust mites were found. However, by September 1st,
data from experimental plots suggested that chlorobenzilate was losing its
advantage and during late September and October it appeared both in ex-
perimental plots and commercial spray operations that zineb, zimix, chloro-
benzilate, and/or combinations with chlorobenzilate were all equally ef-
fective even when high populations of rust mites were encountered.

LITERATURE CITED
Fisher, Fran E. 1957. Control of citrus fruit russet in Florida with zineb.
Phytopath. 47 (7):433-437.
Griffiths, J. T. 1960. Field experience on some new miticides during the
past twelve months on citrus in Florida. Fla. Ent. 43 (1):29-35.
Johnson, R. B., J. R. King, and J. J. McBride, Jr. 1957. Zineb controls
citrus rust mite. Proc. Fla. St. Hort. Soc. 70:38-48.
Johnson, R. B. 1960. The effect of copper on rust mite control with four
rust mite miticides. Proc. Fla. St. Hort. Soc. 73:84-89.
Johnson, R. B. 1961. Spray programs to control citrus rust mites in
Florida Jour. Econ. Ent. 54(5):977-979.


Vol. 45, No. 2











HATCHING OF THE EGGS OF THE EASTERN TENT
CATERPILLAR, MALACOSOMA AMERICANA (F.)
(LEPIDOPTERA : LASIOCAMPIDAE)

L. A. HETRICK
College of Agriculture, University of Florida

The eastern tent caterpillar has a single annual generation wherever it
occurs on rosaceous trees in North America. It is one of the first insects
to exhibit activity in the spring of the year. Eggs hatch when foliage of
the host trees provides a minimum of food for the young larvae, and egg
masses within a geographical locality hatch within about 48 hours of each
other. As the spring season progresses, larval development is completed,
cocooning and pupation occur, and adults emerge to mate and produce the
masses of eggs on host twigs. These eggs remain dormant throughout the
summer, autumn, and following winter. In Florida, the single annual gen-
eration has been completed and eggs have been laid for the following year
before egg hatching has occurred in many Lakes States and New England
locations. The applications of Hopkins (1919) "Bioclimatic Law" are ap-
parent.
Since 1949, the activity of the eastern tent caterpillar has been observed
on host trees (wild cherry, Prunus serotina Ehrh., and wild plum, Prunus
angustifolia Marsh.) at Gainesville, Florida. Hatching dates of egg masses
have been recorded each year. At Gainesville, the date of hatching varies
from late January to late February in different years; the average for the
13 years of observation being during the first week of February. The vari-
ation of hatching dates suggested the need of a study of climatological data
for these years.
Flemion and Hartzell (1936) have reported on studies of the effect of
low temperatures in shortening the hibernation period of insects in the
overwintering egg stage. Part of their work involved observations of the
eggs of eastern tent caterpillar in a single season in New York State. Egg
masses were treated for 8 to 12 weeks at temperatures of 1, 5, 10C. It
was found that time to hatching decreased (on exposure to room tempera-
tures) as the period of low temperature treatment was increased.
Hodson and Weinman (1945) have reported on studies of the closely re-
lated forest tent caterpillar, Malacosoma disstria Hbn., in Minnesota. Their
studies indicate that embryonic development within the eggs is completed
within two to three weeks after the eggs have been laid in July. Diapause
then lasts until the following spring when temperatures and plant develop-
ment are favorable for the young caterpillars. The eggs tolerate a wide
variety of weather conditions, must be exposed to freezing temperatures
and hatching is stimulated by temperatures in the range of 500 to 770F.
U. S. Weather Bureau records for Gainesville for the years 1948 through
1961 were examined. First temperatures in the near-freezing range in
autumn seemed to be a logical starting point for temperature calculations.
The date of such temperatures varied from November 1 in 1955 to December
26 in 1949. The average date for the first frost at Gainesville is December
4th. Oddly enough, the average date for the last frost is February 22nd
at Gainesville; usually occurring after egg hatch in any year. Yet reduction












The Florida Entomologist


in numbers of eastern tent caterpillar larvae by low temperatures has not
been observed locally.
Calculations of daily means from the date of first near-freezing tempera-
tures were made but proved cumbersome. Since such temperatures were
not experienced until after the winter solstice in 1949, it was decided to
begin computations of daily means for all years with the winter solstice.
Furthermore, plant development is controlled by photoperiodism as well
as temperature; egg masses of eastern tent caterpillar do not hatch until
a minimum of new foliage on the trees is available as food. A mean of
50'F was arbitrarily selected as the point of critical insect development.
Table 1 compares the calculations for the different years.

TABLE 1.-ACCUMULATED DAYS AND MEAN TEMPERATURES* BETWEEN WIN-
TER SOLSTICE AND HATCHING OF EGGS OF EASTERN TENT CATERPILLAR
AT GAINESVILLE, FLORIDA.

Accumu-
Days Accumu- lated Average
Mean lated Mean Daily
Year and Total above Mean Degrees Accumu-
hatch date days 50' degrees above 50 lation

1949, Feb. 5 46 42 2899.0 624.5 69.20
1950, Jan. 28 38 37 2535.5 637.5 69.60
1951, Feb. 11 52 41 2932.0 406.5 61.3'
19.52, Feb. 10 51 43 3080.0 556.5 63.8'
1953, Jan. 30 40 32 2329.5 358.0 63.6'
1954, Jan. 27 37 30 2196.0 362.5 63.2'
1955, Feb. 6 47 35 2619.0 382.5 62.5'
1956, Feb. 5 46 33 2515.5 278.0 60.6'
1957, Jan. 31 41 35 2485.0 472.0 67.2'
1958, Feb. 24 65 27 3238.0 231.5 56.8'
1959, Feb. 4 45 35 2529.0 351.5 63.3'
1960, Feb. 8 49 39 2799.0 422.5 62.6'
1961, Feb. 15 56 37 2944.0 249.0 62.4'


Average 47.15 35.85 2700.1 410.2 63.6'

Recorded in degrees Fahrenheit.

Of these years, 1955 most nearly approaches the "average" year with
eggs hatching on February 6th. Numerous departures from the "average"
are apparent for the different years. Obviously, temperatures are not the
only factor involved in stimulating the hatching of these eggs.
Precipitation records for these years were examined. Rainfall during
the period under consideration varied from less than an inch in 1957 to
more than 9 inches in 19,52 and offers less correlation than temperatures;
Temperatures would probably be more reliable if we had an accurate
record of them for the micro-environment of the egg masses. Tempera-
tures of the egg masses would hardly be the same as those recorded on
U. S. Weather Bureau thermometers, as is certainly obvious when one con-


Vol. 45, No. 2









Hetrick: Hatching of Eggs of Eastern Tent Caterpillar 79

siders the location of the egg masses on the twigs of the host trees. The
dark-colored egg masses are exposed to direct sunlight on bright days and
the temperatures within the egg mass would exceed the maxima recorded
within a thermometer shelter. Likewise the egg masses would be exposed
to lower nocturnal temperatures than the recorded minima. Furthermore,
the U. S. Weather Bureau instrument location was on the campus of Uni-
versity of Florida through 1957. In 1958 the old location was abandoned
and records had to be taken from the new location on the Agricultural Ex-
periment Station Farm approximately 2 miles from the old location.
Flemion and Hartzell (1936) reported that the eggs of eastern tent
caterpillar hatched out-of-doors on April 1, 1936, at Yonkers, N.Y. The
U.S. Weather Bureau does not maintain a recording station at Yonkers.
However, Mr. Keith Butson, Florida State Climatologist, secured daily
temperature data for this period from nearby stations at Scarsdale and
Mt. Vernon, N.Y. Mt. Vernon is four miles southeast of Yonkers and
Scarsdale is six miles northeast of Yonkers and six miles north-northeast
of Mt. Vernon. By averaging daily temperatures from these two stations
beginning December 22, 1935, through the hatch date of April 1, 1936,
Yonkers temperatures have been approximated.
Dr. A. T. Drooz, U.S. Forest Service Entomologist (personal communi-
cation), provided the following hatching dates for eastern tent caterpillar;
Confluence, Penn. April 8, 1959, and Harrisburg, Penn. April 13, 1960.
Daily U.S. Weather Bureau records were consulted for these locations.
Table 2 presents information for the New York and Pennsylvania records.

TABLE 2.-ACCUMULATED DAYS AND MEAN TEMPERATURES* BETWEEN WIN-
TER SOLSTICE AND HATCHING OF EGGS OF EASTERN TENT CATERPILLAR.

Accumu-
Accumu- lated Average
Location, Days lated Mean Daily
year, and Total Mean Mean degrees Accumula-
hatch date days above 50' degrees above 50 tion

Yonkers, N.Y.
1936, April 1 102 8 3141.0 26.5 30.8

Confluence,
Penn.
1959, April 8 108 6 3360.5 18.0 31.0

Harrisburg,
Penn.
1960, April 13 114 9 3946.0 59.5 34.60

Recorded in degrees Fahrenheit.

The difference in total days between the winter solstice and egg
hatching at Gainesville, Florida, and the New York and Pennsylvania lo-
cations correlates very nicely with Hopkins "Bioclimatic Law." It is ob-
vious that the arbitrarily selected 50 F temperature has little significance.
The accumulated daily mean degrees are fairly consistent, especially when










The Florida Entomologist


one considers the variation in this category in different years at the Gaines-
ville location. The average, daily temperature accumulations are also in-
dicative of correlation. The importance of temperature, from the time
of the winter solstice to the hatching of the eggs of the eastern tent cater-
pillar, is apparent in stimulating both the insect and the vernal development
of the host plants.
Hatching dates of the eggs of the eastern tent caterpillar need to be
studied over a series of years at other locations within the extensive range
of this insect. Temperature calculations at these other locations could then
be made and compared with calculations for the Gainesville area to obtain
a fuller understanding of the operation of this factor on development.

LITERATURE CITED
Flemion, F., and A. Hartzell. 1936. Effects of low temperatures in short-
ening the hibernation period of insects in the egg stage. Contrib.
Boyce Thompson Institute 8:167-173.
Hodson, A. C., and C. J. Weinman. 1945. Factors affecting recovery from
diapause and hatching of the eggs of forest tent caterpillar, Mala-
cosoma disstria Hubner. Tech. Bul. Minn. Agric. Expt. Sta. 170.
Hopkins, A. D. 1919. The Bioclimatic Law as applied to entomological re-
search and farm practice. Sci. Monthly 8:496-513.


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SOME EGGS OF INSECTS THAT CHANGE COLOR
DURING INCUBATION

ALVAH PETERSON 1

Fertile eggs of some insects undergo a change in color during their in-
cubation period. So far as observed these eggs in nature occur in open
places where they are exposed to variations in sunlight, moisture and air
movement. Examples of these are found among species that belong to one
or more families of the Homoptera, Hemiptera, Lepidoptera, and Neurop-
tera.
The visible colored pigment of an insect egg is often a part of the
chorion and seen through the thin, outer, transparent, adhesive covering
which is usually present. If the chorion is without color and translucent
or transparent then the produced color is located on the embryonic nymph
or larva.
When the chorion is opaque the original deposition color of the egg
usually remains unchanged during incubation. Many examples of these
occur among the Orthoptera, Coleoptera, Hemiptera, Homoptera and Lepi-
doptera, but there are some exceptions to this generalization such as the
exposed overwintering eggs of many Aphididae (Homoptera) which are
black or a very deep brown. At deposition time they may be cream col-
ored, green or a light brown. For example the eggs of the apple grain
aphid, Rhopalosiphum fitchii (Sanderson) and the apple aphid, Aphis pomi
DeGeer, on twigs of apple trees are green when deposited, while the eggs
(3)2 of Longistigma caryae (Harris) on twigs of sycamore (plane) trees
are light brown. A few days to several weeks after deposition these colors
change to black or near black. The pigment in these eggs is located in the
tough, membranous chorion which is completely covered with a thin, trans-
parent, adhesive coat secreted by the female when the egg is deposited.
Upon exposure to air it hardens and glues the egg to the twig or leaf. It
also serves as an insulation against evaporation of the embryonic fluid.
Among some species the external adhesive covering is very sticky and dries
slowly. This is the case with the eggs of Longistigma caryae (Harris).
It is not unusual to find eggs of this species covered with numerous grey
or brown dust particles, especially if the host plant is adjacent to a dusty
field or road.
Eggs of the carpenter worm moth, Prionoxystus robinae (Peck), Cossi-
dae-Lepidoptera, possess opaque chorions which undergo the following se-
quence of change in color: at deposition time they are a light beige color;
two or more days later the overall color ranges from cocoa brown to a deep
chocolate brown. The darkening of the chorion within the numerous tiny
depressions scattered over the eggs produces the change in color.

1 This investigation was in part supported by a research grant from the
National Science Foundation assigned to the Ohio Historical Society Mu-
seum Columbus, Ohio. The author is indebted to C. P. Kimball for the
determination of the species of moths whose eggs are included in this publi-
cation.
SNumbers in parentheses refer to figures.














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Peterson: Some Eggs of Insects That Change Color 83

Eggs of most Saturniidae and Citheroniidae (Lepidoptera) possess
opaque colored chorions that undergo little or no change in color. The
egg of the io moth, Automeris io (Fabr.), is an exception (13-14). Upon
deposition it is completely white except for a small yellow spot on the top
and larger, transverse, translucent, yellow spots on the sides near the top.
Three or more days after deposition the small spot on the top changes t6
black while the larger spots on the sides take on an orange tint due to a
change of color in the developing larva within, which is visible through the
translucent spots.
The most striking and ornate changes in color during incubation take
place among light colored eggs that possess translucent or nearly trans-
parent chorions and are coated evenly with external, transparent, adhesive
coverings. Some species of Hemiptera, especially members of the Pentato-
midae and Lygaeidae, numerous species of Lepidoptera belonging to several
families and species of Mantispidae (Neuroptera) possess eggs of this type.
Light-colored eggs of many species of Pentatomidae undergo a color
change during incubation. The following are a few examples: Nezara
viridula (L.), the southern green stink bug, deposits a mass of yellow eggs
(1) in a flat, uniform, geometrical pattern. A day or two prior to hatch-
ing, each fertile egg (2) from a top view shows two conspicuous, red eye
spots, a much larger red area between the eye spots and a single, faint,
near-black, egg burster. A similar change occurs among the greenish yel-


PLATE I
Figure 1. Top view of several, newly deposited, light yellow, stink bug
eggs, Pentatomidae, Nezara viridula (L.).
Figure 2. Top view of several stink bug eggs ready to hatch. Each
egg exhibits two red eye spots and a large median red area located on
the first instar nymph and a tiny, near-black, egg burster on the pronymph.
Pentatomidae, Nezara viridula (L).
Figure 3. Aphid eggs on a small twig of a sycamore (plane) tree.
In this photograph the newly deposited, light brown, eggs are laid on top of
older black eggs. Aphididae, Longistigma caryae (Harris).
Figure 4. Top view of several, pea-green, stink bug eggs. Two red
pigment streaks appear a day or two before the eggs hatch. Pentatomidae,
Oebalus sp.
Figure 5. Top view of a hatched phalaenid egg showing a typical
emergence hole, vertical ridges, and transverse striae. The translucent
character of the chorion makes it possible to see the color of the pigment
associated with the embryo. Phalaenidae. Eutisanotia unio Hbn.
Figure 6. A group of semi-transparent, flat, disc-like, adhesive, moth
eggs deposited on polyethylene. Light from below makes it possible to
see the developing embryos. Pyralidae, Udea rubigales (Gn).
Figure 7. Top view of two, nearly spherical, somewhat translucent,
moth eggs photographed a few hours previous to hatching. The pigmented
head capsules of the first instar larvae are visible. Notodontidae, Hetero-
campa astarte Dbldy.
Figure 8. Top and side views of near white, phalaenid eggs about to
hatch. The black pigment on the head capsules and pronota of the first
instar larvae are visible through the semitransparent chorion. Phalaenidae,
Ulolonche culea (Gn.)
Figures 9 and 10. Greatly enlarged views of a few mantispid eggs de-
posited on thread-like stalks and in a dense mass. Figure 9, newly de-
posited, near white eggs. Figure 10, eggs ready to hatch. The brown
pigmented bands with white spots are located on the first instar larvae and
are visible through the chorion. Mantispidae, Mantispa interrupt Say.

























































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Peterson: Some Eggs of Insects That Change Color 85

low eggs of Euschistus servus (Say). Two small red eye spots and a sin-
gle faint T-shaped egg burster appear on the top side of each fertile egg.
New eggs of Oebalus pugnax Fab. have a uniform green color. Previous
to hatching the nymphs within become reddish green. This color may be
seen through the chorion. An unknown species of Oebalus produces two,
parallel, red pigment lines (4) across the top of each green egg. Eggs of
Mermidea pectiventris Stal. are light red or pink when deposited. They
change to a deeper red a day or two before hatching. After the red nymphs
of this species hatch the empty egg shells have a translucent, greenish-
white hue.
Several species of Lygaeidae also show changes in color during incuba-
tion. For example, the eggs of the small milkweed bug, Lygaeus kalmii
Stal. are a light, cream white when deposited. Previous to hatching the
three red lines on the abdomen of the first instar nymph are visible through
the chorion and the outer, transparent, slightly adhesive coat. Also the
eggs of the larger milkweed bug, Oncopeltus fasciatus (Dallas) are yellow
to light orange when deposited. Prior to hatching the eggs are distinctly
red due to the overall red abdomen and the colored appendages of the first
instar nymph within.
Moths among several families of Lepidoptera possess eggs with trans-
lucent or nearly transparent chorions and uniform, external, transparent,
adhesive coverings. Figure 5 illustrates the nearly transparent chorion


PLATE II
Figure 11. Several, nonadhesive, unattached, nearly spherical, shiny
acrolophid eggs. When deposited they are near white (note three speci-
mens). A few hours after deposition they change to a deep brown or near
black (remaining specimens). Acrolophidae, Acrolophus propinquus Cram.
Figure 12. Several, nonadhesive, unattached, oval, crambid eggs pos-
sessing longitudinal ridges and transverse striae. All are near white (see
two specimens) when deposited. The remainder have changed to a deep
red. This change usually occurs forty-eight hours after deposition. Pyra-
lidae, Crambus sanfordellus Klots.
Figures 13 and 14. Top views of white io moth eggs firmly attached
to a substrate and to each other. Figure 13, these eggs are one to three
days old and each egg shows a light yellow spot on top and very faint,
translucent, yellow spots on the two slightly flattened sides. Figure 14,
these eggs are four or more days old and each shows a black spot on the
top and translucent orange spots on the sides. Saturniidae, Automeris io
Fabr.
Figures 15 and 16. Top views of a small cluster of circular notodontid
eggs deposited on polyethylene. Figure 15, newly deposited yellowish-
green eggs. Figure 16, the same eggs photographed a few hours prior
to hatching; most of the specimens show rings of red pigment adjacent to
the outer margins. Notodontidae, Heterocampa umbrata Wlk.
Figures 17 and 18. Top and side views of several caenurginid eggs loose
in a glass dish. Figure 17, newly deposited pea-green eggs. Figure 18,
similar eggs forty-eight hours after deposition show a mixture of light
green, pink to cream colored areas flecked with a number of irregular and
scattered brown spots. Phalaenidae, Caenurgina crassiuscula Haw.
Figures 19 and 20. Enlarged views of several adhesive Agrotis eggs.
Figure 19, newly deposited near-white eggs attached to a substrate and
to each other. Figure 20, similar eggs forty-eight hours after deposition
show through the chorion single, irregular, brown spots at their centers
and continuous, irregular, reddish-brown rings about their margins. Pha-
laenidae, Agrotis ypsilon Rott.












The Florida Entomologist


of a hatched egg of Euthisanotia union Hbn., Phalaenidae. Before hatching
the color of the developing larva was readily visible within the egg shell.
The color change in moth eggs of this type may be uniform and involve the
entire embryo or the colored pigment may be scattered or distributed in a
symmetrical pattern.
Species of Acrolophus and Crambus are good examples where the entire
egg undergoes a uniform color change 6 to 48 hours after deposition. Two
species of Acrolophidae, Acrolophus plumifrontellus Clem. and Acrolophus
propinquus Wlshm. (11) are near white when deposited. Six to 12 hours
after deposition the color of the entire egg changes to a very dark brown
or black. Several species of Crambus, Pyralidae, deposit near white to
cream colored nonadhesive eggs. These change to orange, pink or red
within 48 hours after they are laid (12).
Eggs of most species of Geometridae and Sphingidae have a uniform
color which maybe some shade of green to cream color. Among a few it
has been noted that the entire color of the egg may change to a uniform
orange, red, brown or a deep purplish brown a few hours before they hatch.
The green eggs of Euchlaena muzaria (Wlk.), Geometridae, turn red while
the green eggs of Pachysphinx modest Harr., Sphingidae, transform to a
deep brown before they hatch.
Some of many species of Arctiidae, Notodontidae, Olethreutidae, Phalae-
nidae, and Pyralidae possess first instar larvae with dark-colored heads
and in some cases dark tufts of setae. Previous to hatching these are vis-
ible (7, 8) in varying degree through the translucent or nearly transparent
chorions and the outer adhesive coats. When eggs are in this state of de-
velopment they are often referred to as the "black spot stage."
The color pattern of the eggs of many species of Phalaenidae and a few
Notodontidae is very striking during incubation, especially among species
that deposit eggs that are light in color-white, cream, or green. These
eggs from a top view may exhibit red to brown pigment spots. These
spots may be arranged in an irregular manner (18) or they may be quite
uniform in shape and distribution (16, 20).
Eggs of some moths, especially many species of Pyralidae and Olethreu-
tidae, are thin, scale-like, nearly transparent and may overlap when de-
posited in clusters. When these eggs are deposited on green plant tissue
their color will appear green. If deposited on clear polyethylene or glass
their color will be that of the object below the clear substrate. In other
words, the color of the eggs varies with the color of the substrate which
is visible through the eggs.
Many of these semitransparent, thin, scale-like eggs also exhibit nicely
the gross changes that take place in the developing embryos, especially if
the eggs are deposited on a clear substrate so that light from below may be
used when they are observed (6).
Among the Neuroptera, the stalked eggs of Mantispa interrupta Say
and Mantispa viridis Walk. are white and deposited in large, flat, dense
clusters, 2,000 to 4,000 eggs, on foliage and elsewhere. These eggs dur-
ing incubation may change to a very light beige color. A day or two before
hatching, each fertile egg shows several transverse brown bands with light
spots (9-10). These brown marks are on the pigmented segments of the
first instar larvae and are visible through the semitransparent chorions.


Vol. 45, No. 2










Peterson: Some Eggs of Insects That Change Color 87

The foregoing insect eggs, discussed or figured, illustrate the changes
in color that occur among some eggs of insects during their incubation
period. Further investigations should reveal that the eggs of many species
in numerous families undergo a color change during incubation.

SOME PUBLICATIONS ON EGGS OF INSECTS BY ALVAH PETERSON
1917. Studies on the morphology and susceptibility of the eggs of Aphis
avenue Fab., Aphis pomi DeGeer and Aphis sorbi Kalt. Jour. Econ.
Ent. 10:555-560.
1918. Some studies on the eggs of important apple plant lice. N.J. Agric.
Expt. Station Bul. 332, p. 5-63.
1920. Some studies on the influence of environmental factors on the hatch-
ing of the eggs of Aphis avenue Fab. and Aphis pomi DeGeer. Ann.
Ent. Soc. Amer. 13:391-400.
1923. The peach tree borer in New Jersey (with notes on eggs and their
parasites). N. J. Agric. Expt. Sta. Bul. 391, p. 3-141.
1930. A biological study of Trichogramma minutum as an egg parasite of
the oriental fruit moth. U.S.D.A. Tech Bul. 215.
1960. Photographing Eggs of Insects. Fla. Ent. 43(1):1-7.
1961. Some types of eggs deposited by moths, Heterocera-Lepidoptera.
Fla. Ent. 43(3):107-112.








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FIVE NEW CHIRONOMIDAE (DIPTERA) FROM FLORIDA

ELISABETH C. BECK
Florida State Board of Health
Bureau of Entomology

The following five new species of Chironomidae have been discovered
in the course of routine examinations of material from mosquito light traps
operated by the Florida State Board of Health, Bureau of Entomology.
Disposition of types is indicated in parenthesis after data: United States
National Museum (USNM), University of Florida Collections (UF), Dr.
James E. Sublette (JES). All other types are in the collection of the Flor-
ida State Board of Health, Bureau of Entomology.
The following abbreviations (following Dendy and Sublette, 19592), are
used: LR, leg ratio; AR, antennal ratio; DM, dorso-median; DL, dorso-
lateral; PA, prealar.

Chironomus (Dicrotendipes) lobus, new species
MALE HOLOTYPE: Ozello, Fla., June 16, 1961 (USNM).
Wing length 2.0 mm; AR 2.0; LR, 1.5. Frontal tubercules minute. Pro-
notum narrow, slightly projecting medially.
Head and thorax yellow-brown; antennal flagellum and pedicel dark
brown; palpi light brown; thoracic vittae, pleural markings, sternum, and
postnotum blackish-brown. PA bristles 4; DL bristles approximately 10,
in single row.
Abdomen dark brown. Wings light brown, the veins brown. Legs
light brown, the fore tibia and all tarsi darker.
Genitalia: (Fig. 1). Dark brown, the tip of ninth tergite and the anal
point blackish. Similar to Chironomus modestus Say, but setae on inferior
appendage not in two rows. Dististyle about 4.5 times long as wide; su-
perior appendage large, heavily coated with microtrichia.
FEMALE: Unknown.
Paratypes: 3 males, Allenhurst, Fla., Jan. 13, 1961; 2 males, Siesta
Key, Fla., Oct. 4, 1960; 2 males, Punta Rassa, Fla., Apr. 15, 19.58; 1 male,
Everglades City, Fla., Nov. 1, 1957, 3 males, Nov. 1, 1960 (one UF, one
JES); 1 male, Port Richey, Fla., Mar. 22, 1955, 1 male, Nov. 11, 1955, 2
males, Apr. 22, 1958; 1 male, Ozello, Fla., Sept. 15, 1960, 1 male, Jan. 13,
1961; 1 male, Santa Rosa, Fla., Aug. 4, 1961.
Abdomen varied from olive-brown to dark brown. Wing length, range,
1.45-2.3; mean 1.8 (13); leg ratio, range, 1.2-1.6; mean 1.4 (3); antennal
ratio, range 2.0-2.2; mean 2.0 (11). The dististyle typically is obliquely
truncate at apex, making the style appear shorter and broader than shown
in Figure 1. The species apparently occurs throughout the year.
Diagnosis: The broad, heavily setose superior appendage is distinctive.

1 This investigation was supported in part by U. S. Public Health Serv-
ice Grant E-4098, from the Institute of Allergy and Infectious Diseases.
"Dendy, J. S., and J. E. Sublette, 1959. The Chironomidae (=Tendipedi-
dea: Diptera) of Alabama with descriptions of six new species. Ann. Ent.
Soc. Amer. 52(5): 506-519.












The Florida Entomologist


Male genitalia, Chironomus lobus, n. sp.
Wing, Polypedilum parascalaenum, n. sp.
Male genitalia, Polypedilum parascalaenum, n. sp.
Male genitalia, Chironomus alatus, n. sp.
Male genitalia, Chironomus boydi, n. sp.
Male genitalia, Tanypus clavatus, n. sp.


Figure
Figure
Figure
Figure
Figure
Figure


Vol. 45, No. 2













Beck: New Chironomidae (Diptera) from Florida 91

Polypedilum (Polypedilum) parascalaenum, new species
MALE HOLOTYPE: Jackson Co., Fla., Woodruff Dam light trap #2,
July 21, 1961. (USNM). Wing length 1.3 mm., LR ? (fore tarsi missing),
AR 1.1.
Head, thorax, scutelum yellow-brown; abdomen brown; pedicel of an-
tennae, thoracic vittae, sternum, pleural markings and postnotum blackish-
brown. DL bristles in single row of 9-12 bristles. PA bristles 4. Mesono-
tum with pale pruinescense posteriorly. Halteres light brown.
Legs dark brown, the femora with pale subapical ring, the tibiae with a
pale basal ring.
Wings with RI and R2&, distinctly separated at apex; conspicuously
marked with gray. (Fig. 2).
Genitalia: (Fig. 3). Anal point without teeth on base, superior ap-
pendage large, rounded, with dense microtrichia.
FEMALES: Similar to male, except more distinctly marked.
Paratypes: 2 females, Blountstown, Fla., Nov. 4, 1961; 2 females,
Woodruff Dam light trap #6, May 15, 1956; 2 females, Chattachoochee,
Fla., May 19, 1961.
Diagnosis: The wing markings on this species are distinctive.

Chironomus (Cryptochironomus) alatus, new species
MALE HOLOTYPE: Lake Worth, Fla., Sept. 3, 1957. (USNM).
Wing length, 1 mm.; LR 2; AR 1.5 (paratype).
Head, palpi, thorax, halter, yellowish-brown; pedicel of antennae, anten-
nal flagellum, mesonotal vittae, postnotum dark brown; DL bristles in sin-
gle row of 7 or 8, widely spaced; PA bristles 5.
Abdomen and legs pale brown, the forelegs and apical tarsal segments
darker; mid and hind tibiae with two spines, the inner spine on mid tibia
curved and distinctly shorter.
Wings light brown; the fork of Cu beyond the r-m crossvein; hairs on
anterior wing veins very dark; squama without fringe.
Genitalia: (Fig. 4). Very similar to carinatus (Townes), differing in
that the apex of the superior appendage is much broader and turns out-
ward, and the ninth tergite lacks a median setiferous ridge.
FEMALE: Unknown.
Paratypes: 2 males, Lake Worth, Fla., Aug. 2, 1957; 2 males, Goose
Prairie, Fla., Aug. 2, 1957, 3 males, Sept. 13, 1960. (one UF, one JES).
Wing length, range 1.0-1.1; mean 1.06 (5); AR 1.5 (1).
Diagnosis: This species is very similar to carinatus, but is smaller,
has a shorter spine on the middle tibia (carinatus has a shorter spine on the
hind tibiae), and has a broader, bent apex to the superior appendage of the
male genitalia.

Chironomus (Cryptochironomus) boydi, new species

MALE HOLOTYPE: Palm Beach Co., Fla., Pump Station S-5A, Conserva-
tion area #1, Sept. 9, 1960. (USNM).
Wing 1.5 mm.; LR 1.8 (paratype); AR 2.0.
Head, thorax, abdomen pale greenish stramineous; pedicel ochraceous;
antennal flagellum brown; mesonotal vittae, sternum, and postnotum












The Florida Entomologist


orange; halteres green; PA bristles 4-6; DM bristles in staggered double
row; DL bristles in a single row.
Legs pale greenish, fore legs and apical tarsi on all legs medium brown;
two spines on each hind tibia, apparently only 1 spine on mid tibiae.
Wings light brown; veins only slightly darkened; fork of Cu beyond
r-m crossvein; M ending at wing apex; squama with only 4-5 hairs.
Genitalia: (Fig. 5). Style with a very distinct inner lobe; anal point
broad, with a separate dorsal point bearing many microtrichia; superior
appendage very inconspicuous, a broad lobe bearing one seta.
FEMALE: Unknown.
Paratypes: 2 males, same data as holotype (one UF); 4 males, Grant,
Fla., Jan. 13, 1961 (one JES); 1 male, Belle Glade, Fla., July 17, 19,56.
Wing length, range, 1.5-1.6; mean 1.55 (4); LR 1.9 (1); AR, range 1.8-
2.2; mean 2.0 (4).
Diagnosis: This species can be readily separated from all other known
species of this genus by the very distinctive shape of the style.
I take pleasure in naming this species in honor of Dr. Mark F. Boyd.

Tanypus clavatus, new species

MALE HOLOTYPE: Santa Rosa, Fla., Apr. 15, 1961 (USNM).
Wing length 2.1 mm., LR 0.73. Pronotum slightly produced at apex.
Head and mouthparts light brown, pedicel fuscous. Mesonotum buff
with blackish-brown vittae, pleural markings, sternum, and posnotum.
Mesonotal tubercule very distinct, lighter than vittae. DL in single row to
just anterior to scutellum, where they form a clump of 5-6. Scutellum dark
medially, pale laterally.
Abdomen dark brown, blackish at incisures. Legs dark brown. Wings
pale brown, r-m crossvein dark, anterior veins brown, posterior veins paler;
indistinct brown spots: three in cell R5, two in M, one in Cu, and four or
five in anal cell. Halter stem yellow, the knob brown.
Genitalia: (Fig. 6). Dististyle curved, tapering to sharp-pointed apex
with blunt, dark spine; large dense patch of setae along inner ventral sur-
face of basistyle; the chitinized supports in base of basistyle black and
club-shaped.
FEMALE: Similar to male except for usual sexual differences.
Paratypes: 1 male, Port Richey, Fla., Mar. 7, 1961 (UF); 2 males,
Santa Rosa, Fla., Dec. 13, 1955, 1 male, Mar. 2, 1956, 1 male Apr. 25, 1961,
1 male, Mar. 28, 1961; 1 male, Ozello, Fla., Feb. 24, 1961; 3 males, Apalachi-
cola, Fla., Feb. 24, 1961; 1 male, Everglades City, Fla., Dec. 6, 1955 (JES),
1 male, Jan. 20, 1961, 1 male, Feb. 5, 1961, 1 male, Feb. 25, 1961.
Wing length, range, 2.1-2.3; mean, 2.2 (5); LR, range, 0.67-0.73; mean,
0.70 (6). In most specimens the mesonotal vittae and postnotum are black.
PA bristles range from 4-7.
Diagnosis: The black mesonotal vittae, indistinct wing spots, and male
genitalia serve to distinguish this species from all other known Tanypus.


Vol. 45, No. 2



















THE EFFECT OF AGE AND TIME OF DAY ON THE
AVIDITY OF AEDES AEGYPTI

H. K. GOUCK AND CARROLL N. SMITH
Entomology Research Division, Agricultural Research Service,
United States Department of Agriculture

Laboratory experiments were conducted to determine the effect of age
and time of day on the avidity of Aedes aegypti (L.) in connection with
studies on the effectiveness of mosquito repellents.
Two series of biting-rate tests were conducted in which the arms of
research subjects, freshly treated with marginal dosages of dimethyl
phthalate, were exposed to mosquitoes of various ages. Eight subjects
were used in the first series and three in the second. The forearms of the
subjects were each treated with 1 ml. of a 25% solution of dimethyl phthal-
ate in ethanol. Past experiments have often demonstrated that such a
dosage is adequate to repel mosquitoes that are not particularly avid; how-
ever, it would not repel mosquitoes of average avidity. Several hundred
adult mosquitoes were allowed to emerge from rearing pans into test cages
over a period of 24 hours, after which no new mosquitoes were added. Each
cage was provided with water and honey solution. Twenty-two cages were
used in the first series and eight in the second. Morning and afternoon
tests were made by each subject daily, from the second to the seventh day
in eight of the cages in the first series, and from the fifth to the tenth day
in six of the cages in the second series, a total of 64 tests each morning
and each afternoon in the first series and 18 in the second. Opposite arms
were used for the two daily tests to avoid any carry-over of repellent from
the morning to the afternoon. Exposures were begun within a few minutes
after treatment and continued for three minutes, or for the time required
to receive ten bites, whichever was shorter, and the avidity, or biting rate,
was expressed as the number of bites per minute. The average biting rates
at various ages are shown in the table.
In both the morning and afternoon tests, taken separately, the avidity
increased rapidly with age for the first five or six days, then remained
fairly uniform or increased slightly through the ninth day. However, the
avidity each morning was much lower than during the previous afternoon,
despite the additional age. It was concluded that in order to obtain maxi-
mum uniformity in repellent studies with this species the mosquitoes
should be from seven to eight days of age, the dosages of repellent should
be low enough to permit the completion of testing in a morning or an after-
noon, and comparisons should not be made between morning and afternoon
tests.













The Florida Entomologist


Age Morning Afternoon
(days) tests tests


First series

0.04
.27
.74
3.55
8.99
8.90

Second series

1.50
4.50
8.39
9.67
10.20
14.78


0.43
1.99
5.35
17.27
24.60
23.83


8.76
17.19
19.17
20.04
23.67
27.78


Vol. 45, No. 2












Book Review


(Continued from Page 65)
system. The book can be arranged with families (or fascicles) arranged
alphabetically, phylogenetically, or by pages as issued. Revisions of sep-
arate fascicles are possible with this arrangement and they can be added
with other notes to the loose leaf scheme. Each fascicle is arranged accord-
ing to the following pattern: 1) family name, describer, date, and common
name, 2) family synonymy, 3) general features of family, 4) description
(morphological), 5) ecology, 6) status of classification, 7) general distribu-
tion and number of species, 8) key to genera in U. S., 9) classification of
U. S. genera, and 10) references. Few typographic errors were noted in
the two parts, and those in Part I were corrected on the first page of Part
II. The author has done a fine job in organization which greatly enhances
the usefulness of the complicated subject matter.
The author has spared no effort in trying to make this reference as
complete and accurate as possible, consulting 45 outstanding American
and European coleopterists on their respective specialties. However, the
author is responsible for the organization and final form. The one excep-
tion to this is the fascicle treating the Carabidae which is entirely the work
of G. E. Ball. This is an excellent effort on the part of Dr. Ball to bring
our classification up to date on this large and difficult group. It is espe-
cially helpful with its keys and indications, by the author, that certain
genera are in need of revision. Dr. Ball is to be congratulated on the fine
part he played in adding to this book.
The introduction is devoted to external beetle anatomy, a key to the
families of beetles of the world, a listing of families and higher categories
and a bibliography of general works. The entire work is considerably en-
hanced by the general habitus drawings of Miss Eileen R. Van Tassell.
The Catholic University is to be congratulated on its foresight and in-
terest in Dr. Arnett's work and for making such a valuable reference avail-
able to our scientific society.-Robert E. Woodruff.












The Florida Entomologist


A MANUAL OF COMMON BEETLES OF EASTERN NORTH AMERICA, by Elizabeth
S. and Lawrence S. Dillon. Row, Peterson and Co., Evanston, Ill. and
Elmsford, New York, 1961, viii+884 pp., clothbound, illus. $9.25.
For many years anyone interested in beetles had to resort to Blatchley's
monumental Coleoptera of Indiana for information on the common beetles
of the eastern United States. This work is limited essentially to those
found in Indiana, is 50 years out of date, almost impossible to find, and
too expensive for the average entomologist. At last we have a general ref-
erence on beetles which does not have any of these drawbacks of Blatch-
ley's work.
Any person who devotes his valuable time, in this day of rushing, to un-
selfishly write a book such as this, is to be heartily congratulated and
complimented. The Dillons have filled a vast gap in our endeavor to learn
more about one of the most dominant groups of animals on earth. For
example, as the authors state, one family (Curculionidae) contains 50,000
species in the world-more than the combined total of mammals, birds,
reptiles and amphibians!
Many young people are becoming vitally interested in the wonderful
world of natural science and need our encouragement. This book should
stimulate these inquisitive young men and women. Perhaps the greatest
single deterrent to the study of insects is the overwhelming number of
species and the often scattered, unavailable literature dealing with them.
This book brings together much of this information, provides illustrations
of most common species and in general facilitates the study of this inter-
esting group of insects.
Many of the groups of vertebrates have been thoroughly covered in
general manuals, suitable for both the amateur and professional. As Dr.
Ross H. Arnett has put it in a recent review of this book, "The Old World
has long ago put aside such immature notions that the study of beetles
is to be confined to the odd and idle rich or to psycho-ceramic [sic] Gen-
erals. They have long had an abundance of manuals for all levels of study
of this subject. We have never had such a book before; we will never be
without such a book again. This is the beginning. Many more will follow.
The date 1961 marks for beetle study what 1934 marks for bird study.
For this, we shall all be ever grateful to the Dillons!" It may seem un-
usual to quote from another review of the same book, but I can think of
no better testimonial than this.
The book is printed on good quality stock with a convenient generalized
beetle drawing inside front and back covers. There are 544 text figures
and 81 full page plates containing several hundred figures. There is a
good glossary but technical terms are kept to a minimum in the text. The
bibliography is divided into: 1) general, 2) ecology, 3) baits and trapping,
4) arrangement alphabetically by family, 5) state and Canadian lists. A
short appendix contains names and addresses of suppliers of books and
equipment, and the index is quite complete. The introduction contains sec-
tions on collecting, methods and materials, pinning and labeling, structure,
larvae and use of the keys. There is a separate section on ecology of
N. A. beetles.
Any work of this size and scope will naturally contain errors, and this
one is no exception. Later editions undoubtedly will correct many of these.


Vol. 45, No. 2












Book Review


For example, on p. 729, the names for figures 8 & 9 are reversed. Such an
error undoubtedly will cause many misidentifications. The illustrations are
excellent in general, but in some cases were hastily drawn without regard
to specific characters. Figure 15 on plate LV is an example of this. The
genus Thylodrias is described as "wingless" even though a fully-winged
male is illustrated.
The greatest objection I have to the book is the fact that any beetle
can be run through the keys and naturally will come to a species. The
beginner should be cautioned repeatedly that many species not covered in
this book will work through the key and the identification will be incor-
rect. This has been eliminated in part by the illustrations. However,
many groups cannot be determined without the aid of generic revisions or
assistance of a specialist. The genus Phyllophaga and the family Trogidae
are good examples of this. Sixteen species of Phyllophaga are placed in
the key, and four of these are illustrated, although approximately 200
species occur in the United States. I think it would have been simpler and
better for the beginner for the authors to have indicated that it is necessary
to examine the genitalia for identification of species in this genus and the
beginner be referred to a recent revision for specific identification. This
same suggestion holds for the family Trogidae, of which 9 of the 42
United States species are treated. The reader is not warned anywhere
in the keys that he should consult other references or that many species
are not included.
Despite any differences in judgement as to what species are to be in-
cluded, a few mechanical errors and incorrect use of certain generic names,
this book is a must for all interested in the study of beetles. It will be a
welcomed addition to the library of the beginner and the professional,
and should increase the popularity of this diversely interesting group of
insects.-Robert E. Woodruff




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