A REVISION OF THE FLAVIDUS GROUP OF THE GENUS CHRYSOPS MEIGEN (DIPTERA : TABANIDAE)

22 Pages·1999·11.4 MB·

by  T M Baier

PROC. ENTOMOL. SOC. WASH.
101(1), 1999, pp. 175-196
A REVISION OF THE FLAVIDUS GROUP OF THE
GENUS CHRYSOPS MEIGEN (DIPTERA: TABANIDAE)
Tevis M. Baier
Department of Zoology, University of New Hampshire, Durham, NH 03824, U.S.A.
(e-mail: [email protected])
—
Abstract. A taxonomic revision of the Chrysops flavidus species group is provided
with a key to species, descriptions, distribution maps, and illustrations of wings and an-
tennae for each of the nine species currently recognized in this group. The relationships
and identification of these nine species are based on analysis of morphological similarity
involving 13 critical characters. A total of 4,843 specimens from 14 institutions were
examined during this study. Two new species in the Chrysopsflavidus group are described,
Chrysops sandyi and Chrysops tumidicornis, both previously misidentified as Chrysops
atlanticus. The male of Chrysops dixiauus is described for the first time.
Key Words: Diptera, Tabanidae, Chrysopsflavidus group, key to species
The genus Chrysops Meigen is currently includes 7 previoously described species
represented by 87 described species in the and two new species: Chrysops atlanticus
C C
Nearctic Region north of Mexico (Burger Pechuman, brunneus Hine, celatus
C C
1995), and 291 world wide. This genus was Pechuman, dixiauus Pechuman, flav-
C
last revised in North America by Philip idus Wiedemann, pudicus Osten Sacken,
(1955). Philip's revision included a key to and C. reicherti Fairchild, C. sandyi, n.sp.,
95 species and 14 subspecies, with corre- and C. tumidicornis, n. sp. I will redescribe,
sponding notes on these taxa, and descrip- clarify relationships and summarize the bi-
tions of 4 new species and 5 new subspe- ology and geographic distribution of this
cies (but it also treated species from Central group. Immature stages and habitat are dis-
America and the Caribbean). cussed under the description of each spe-
Although no one has divided all of the cies.
Nearctic Chrysops into definitive species
groups, some species groups have been rec- Materials and Methods
ognized by tabanid taxonomists. The three I examined 4,843 specimens, (4,684 fe-
commonly used are the Chrysops callidus males and 159 males), from the collections
group, the C. carbonarius group, and the C. listed below. The acronyms are those ofAr-
flavidus group (Pechuman 1949). The C. nett et al. (1993), except for the University
flavidus group is particularly difficult be- of New Hampshire Collection (UNHC).
cause of the large amount of intraspecific
variation within the included taxa. Al- AMNH: Department of Entomology,
though three species have been describedin American Museum of Natural
this group during the past 45 years, no one History, New York, NY; David A.
has studied the group as a whole. Grimaldi.
The Chrysops flavidus group currently BMNH: Department of Entomology, The
176 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
Natural History Museum, Lon- MRSN: Museo Regionale Scienze Natur-
don, U. K.; John E. Chainey. aH, Via Gioletti 36, Torino 10128,
CASC: Department of Entomology, Cali- Italy.
fornia Academy of Sciences, San MZLU: Museum of Zoology, Lund Uni-
Francisco; Paul H. Arnaud, Jr. versity, Helgonavagen 3, S-223
CNCI: Canadian National Collection, 62 Lund, Sweden.
Centre for Land and Biological ZMHB: Museum fiir Naturkunde der
Resources Research, Agriculture Humboldt Universitat zu Berlin,
Canada, Ottawa, Ontario; J. M. Bereich Zoologischer Museum,
Cumming. InvalidenstraBe 43, 1040 Berlin,
CUCC: Department of Entomology, Germany.
Clemson University, Clemson,
SC; Michael A. Floyd. The Chrysopsflavidus group has few dis-
CUIC: Department of Entomology, Cor- tinctive structural characters, and the spe-
nell University, Ithaca, NY; E. Ri- cies can be difficult to identify. Color pat-
chard Hoebeke. terns are important in identification but
FMNH: Division ofInsects, Field Museum must be used with caution because of var-
of Natural History, Chicago, IL; iation. The chaiacters described below are
Alfred F. Newton, Jr. the most useful in separating the species.
FSCA: Florida State Collection of Ar- The morphological terminology used in this
thropods, Division of Plant Indus- paper follows that used by Teskey (1990).
try, Gainesville; G. B. Fairchild. Principal characteristics used are: body
INHS: Illinois Natural History Survey length, in millimeters, from the base of the
Insect Collection, Champaign; antennae to the apex of the abdomen; the
Kathleen R. Methven. size and shape of the scape and pedicel as
OSUC: Ohio State University, Collection well as the length ratio and color of the
of Insects and Spiders, Columbus; scape, pedicel, and flagellum; shape of the
Andrey Sharkov. frontal callus; color of the mesoscutum;
TAMU: Department of Entomology Insect wing pattern, particularly the width of the
Collection, Texas A. & M. Uni- apical spot, the location ofthe outer margin
versity, College Station; Edward of the crossband, and the infuscation of the
G. Riley. 5th posterior cell; color of the hind femur;
UGCA: Entomology Collection, Universi- and abdominal color pattern.
ty of Georgia, Athens; Cecil L. For illustrations, I chose a specimen that
Smith. most closely resembled the description of
UNHC: Entomological Museum, Depart- the holotype. One wing from each specimen
2X2
ment of Zoology, University of was removed, placed between two
New Hampshire, Durham; Donald glass slides and scanned into a Dell 486p/
S. Chandler. 25 computer using MICROTEK Scan-
USNM: National Museum of Natural His- Maker 35t. The scanned picture was printed
tory, Smithsonian Institution. and used as a template for the final drawing.
Washington, DC; R. V. Peterson. The antennal drawings were produced with
a camera lucida.
The following insect collections are also
The locality data from all specimens ex-
cited in this paper:
amined were entered into a database using
MNHN: National Collection of Insects, Wordtech Systems, dBXL®, (a dBASE III
Museum National d'Histoire Na- Plus® compatible format). The information
turelle, 45, Rue Buffon, Paris collected was placed into 9 "fields": spe-
75005 France. cies, country, state, county, town, collector.
VOLUME 101. NUMBER 1 177
apical spot
hyalinetriangle
crossband
5thposteriorcell
ocelli
flagellum pedicel scape
basalcallus
antennalsocket
Figs. 1-3. 1. Wing of Chrysops species. 2, Antenna of Chiysops species. 3, Anterior view of head of
Chrysops species.
museum, count (number of specimens with triangle not crossing vein R2+3, cell br at
identical data), and sex (male or female). least V3 infuscated basally; abdominal ter-
Locality data for specimens I did not ex- gites 2-4 patterned with median inverted
amine were taken from the distribution re- "V" set over pale median triangle.
cords of L. L. Pechuman, now stored in the
Zoology Department at the University of Key to Species of the
New Hampshire. Distribution maps were Chrysops flavidus Group
then produced for each species from the 1. Scape and pedicel distinctly swollen, together
above database and from the records of L. longer than flagellum (Fig. 14). Frontal callus
L. Pechuman. twice as wide as high, with no black markings.
Abdomen with inconspicuous median trian-
Diagnosis of the gles. Wing pattern with extensive apical spot,
reaching crossband posteriorly and enclosing
Chrysops flavidus Group
hyaline crescent (Fig. 23) brunneus Hine
Frontoclypeus glossy yellow with no - Scape and pedicel less swollen, combined
mid-facial stripe; frontal callus yellow to length equal to orshorterthan flagellum. With-
out remaining combination ofcharacters .... 2
light brown, occasionally with brown upper
2. Usual hyaline areas of wing slightly smoky to
margin; frons yellow pollinose; mesoscu- very smoky, outer margin ofcrossband angled
tum with 3 longitudinal stripes, darker than from vein R4 to middle of vein M4 (Fig. 22).
ground color; proepimeron and proepister- Scape and pedicel moderately swollen, com-
nal callosity yellow tomentose with long bined length equal to or rarely longer than fla-
yellow hair; wing pattern with broad apical gellum (Fig. 13). Mesoscutum green-gray iri-
descent with black longitudinal stripes
spot entering 2nd submarginal cell, cross- atlanticiis Pe.c.h.uman
band reaching hind margin ofwing, hyaline - Without above combination ofcharacters ... 3
178 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
3. Mesoscutum greenish gray or steel gray in - Hind femur dark brown basally. Mesoscutum
ground color, longitudinal stripes black. Outer yellow green with brown stripes. Outermargin
margin ofcrossband sinuous 4 of crossband straight, hyaline triangle slightly
- Mesoscutum yellow in ground color, longitu- tinted, cells br and bm V3-V2 and 'A infuscated
dinal stripes brown. Outer margin of cross- basally (Fig. 29). Scape and pedicel not swol-
band, straight, concave, or sinuous 6 len (Fig. 20). Length 5.7-7.5 mm
4. Antenna not swollen, flagellum at least Vs lon- sandyi, n. sp.
gerthan scape and pedicel combined (Fig. 15).
Frontal callus spade shaped, width and height Chrysops atlanticus Pechuman
subequal. Without dark spot under scutellum
(Fig. 4, 13, 22)
celatus Pechuman
- Scape and pedicel slightly swollen to swollen, Chrysops canifrons Walker 1848: 197-198.
combined length subequal to flagellum. Frontal Holotype female: Florida (BMNH). Se-
callus, width and height not equal. Abdomen nior synonym of atlanticus, suppressed
with dark spot under scutellum, often extend-
by the International Commission on Zoo-
ing to lateral edges of tergite 1 5
5. Hyaline triangle not reaching vein R^^,, cells logical Nomenclature, Opinion No. 1711,
brandbm% andV3infuscatedbasally(Fig. 30). 1993.
Scape and pedicel swollen, pedicel barrel Chrysops atlanticus Pechuman 1949: 79-
shaped (Fig. 21). Frontal callus light brown. 82. Holotype female: Rehoboth Beach,
Mesoscutum gray green with black stripes
. . Delaware (CUIC); Jamback and Wall
tumidicomis. n. sp.
- Hyaline triangle reaches vein R2+3, apical spot 1959: 23-24, description of egg, larva
narrowly enters 2nd submarginal cell, cells br and pupa; Teskey 1969: 29-30, descrip-
and bm Vi and '/^ infuscated basally (Fig. 27). tion of larva; Goodwin 1972: 104, de-
Scape and pedicel slightly swollen (Fig.18). scription of pupa.
Frontal callus reddish brown with black upper
—
margin. Mesoscutum steel gray with black Diagnosis. Length 6.5-9.2 mm. Scape
stripes pudicus Osten Sacken
and pedicel moderately swollen, flagellum
6. Abdominal tergites 1-2 light yellow to straw
color, dark inverted "V" on tergite 2 com- equal to length of scape and pedicel com-
pressed, not reaching beyond the middle ofter- bined. Mesoscutum grayish green in ground
gite 2. Flagellum 1.3 to 1.5 times longer than color. Wing pattern with smoky tinge, hy-
scape and pedicel combined 7 aline areas not clearly defined, hyaline tri-
- Abdominal tergites 1-2 yellow, orange orlight angle not extending beyond lower half of
brown, inverted "V" pattern not compressed,
extending beyond the middle of tergite 2 to- 1st submarg—inal cell.
ward anteriormargin. Flagellum equal to orup Female. Light to dark brown, length
to 1.2 times longer than scape and pedicel 8.5-9.2 mm. Scape and pedicel moderately
combined 8 swollen, light brown, basal flagellomere
7. Fifth posterior cell infuscated, outer margin of light brown, apical flagellomeres black,
cirnfoussscbaatnedd sbiansuaolulsy,(cFeilgl.s2b8r).anHdinbdmfeVm3uarndredV-a length of flagellum subequal to combined
dish-brown. Tergites 1-2 straw-colored, medi- length of scape and pedicel, antennal ratio
an anterior portion oftergite 2 with a greenish 15:10:25. Frontoclypeus glossy yellow, eye
mm
cast. Length 8-9.5 reicherti Fairchild margins bearing yellow tomentum that ex-
- Fifth posteriorcell hyaline, vein Cu, infuscated tends medially beneath tentorial pits to
catonbvoerdxe,r,ceolultserbrmaarngdinbomfcViroasnsdban'/d, sitnrfauisgchatteodr frontoclypeal suture. Maxillary palp brown
basally (Fig.25). Hind femur dark brown. Ter- with sparse black hairs. Frons yellow and
gites 1-2 yellow without a greenish cast. gray tomentose with yellow hairs at vertex,
Length 6-8.5 mm dixianus Pechuman width 1.13 times height. Frontal callus ob-
8. Hind femur yellow. Mesoscutum yellow with long, bulbous, light brown, width 1.54
brown stripes. Outer margin of crossband times height. Vertex with glossy black in-
sitnrfauisgchatteodrbcaosnaclalvye(,Ficge.ll2s6)b.rSacnadpebmandV2paednidceVl3 tegument surrounding shining brown ocelli.
slightly swollen (Fig. 17). Length 8-10 mm Mesoscutum grey green iridescent with
fiavidus Wiedemann three black longitudinal stripes, sublaterals
VOLUME NUMBER
101, 1 179
FCigs. 4-9. Distributions. 4, Chtysops atlanticus. 5, C. brunneiis. 6, C. celafus. 7. C. dixianus. 8. C. fiavidiis.
9, pudicus.
—
180 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
wider than median one, scutellum predom- SC, TN, and VA. There are also published
inantly brown, lighter medianly. Legs pre- records for—CT and RL
dominantly yellow, hind coxa and fore ta- Biology. The larvae have been found in
rusi brown, fore tibia with black hair, mid salt marsh and brackish pools. Based on
and hind tibia with mixed yellow and black their narrow distribution along the coast,
hair. Wing pattern with usual hyaline areas they are probably restricted to this saline
smoky, apical spot broad, fading into 2nd environment. Flight times for C. atlanticus
submarginal cell, crossband brown with ir- are between April and September in Loui-
regular outer margin, crossing 1st posterior siana (Tidwell 1973), June to September in
cell at its center, a perpendicular line drawn Virginia (Pechuman 1973), and late May to
from vein R4 to hind margin of wing not mid October in New York (Pechuman
forming line parallel to outer margin of 1981). The adults are abundant during June
crossband, hyaline triangle not extending and July throughout theirrange and are eco-
beyond posterior Vi of 1st submarginal cell, nomically important due to their aggressive
C
discal cell, 4th and 5th posterior cells in- biting behavior. Thirty atlanticus bites
fuscated, 5th posterior cell paler in center, were counted on 1 human in 90 seconds in
cells br and bm % and V3 basally infuscated. a cultivated field near Cedarville, New Jer-
Halter brown stalk yellow-brown knob. sey, (Hansens, 1980). Anderson (1971) de-
First abdominal tergite dark yellow, black scribed C. atlanticus as being autogenous,
haired medianly, tergites 2-5 with subme- depositing the first egg mass before seeking
a blood meal. Subsequent work by Mag-
dian oblique dark spots, gray posterior mar-
gin extending medianly into pale orange, narelli and AndeCrson (1976) concluded that
populations of atlanticus can be main-
equilateral triangle, dark spots on tergite 2
outline triangle and join anteriorly forming tained by the first oviposition, making them
inverted "V" pattern, tergites 3-5 with sub- difficult to control.
median dark spots slightly separated ante- Chrysops atlanticus is not known to
transmit any disease agent in nature; how-
riorly. Sternites 1-2 yellow, sternite 3 mot-
ever, in the laboratory, tests have demon-
tled yellow and brown, sternites 4-7 dark
strated it to be an effective experimental
brown.
— vector of the African filarial worm Loa loa
Male. Similar to female except for usu-
(Orihel and Lowrie 1975).
al sexual differences and following char- Discussion. Chrysops atlanticus is
acteristics. Length 6.5-8 mm. Scape and
most similar to C. sandyi, C. tumidicornis,
pedicel slightly more enlarged with black and to C. brunneus, based on the smoky
hair that is longer and finer than on female. wing pattern, association with a saline en-
Mesoscutum sparsely covered with long vironment, and swollen antennae. Chrysops
yellow hair. Cell br entirely infuscated ex- atlanticus differs from C brunneus in its
cept for a subapical hyaline spot. Abdomen narrower scape and pedicel (Fig. 22) that
with yellow and black hair scattered over when combined are equal in length to the
pattern. — flagellum, moderately inflated frontal cal-
Material examined. 934 9 and 18 6 losity, grayish-green mesoscutum, and wing
examined from the following collections: pattern without clearly defined hyaline ar-
CASC, CNCL CUCC, CUIC, FMNH, eas. Chrysops atlanticus differs from C
FSCA, INHS, OSUC, TAMU, UGCA,
sandyi in its larger size, blackish longitu-
UNHC, USNM.
— dinal stripes on the mesoscutum, and cross-
Distribution. Atlantic coast of North band with irregular outer margin. Chrysops
America from Maine to Florida. I have ex- atlanticus differs from C tumidicornis in its
amined specimens from AL, DE, FL, GA, larger size, less swollen pedicel, smokier
LA, MA, ME, MD, MS, NC, NH, NJ, NY, wing pattern, and lighter abdominal pattern
VOLUME NUMBER
101, 1 181
that does not have a dark spot on tergite 1 rowed laterally, strongly inflated, light
under the scutellum. There appears to be no brown, upper margin dark brown, width
overlap in the geographical distribution of twice height. Vertex dark brown tomentose,
C. atlanticiis with either C. sandy! or C. except glossy around each ocellus, ocelli
tumidicornis. dark brown. Mesoscutum light brown to-
Color variation in C. adanticus is com- mentose and yellow pilose, except lateral
mon throughout its range, making it partic- margins pale yellow-gray tomentose, bear-
ularly difficult to define. The abdominal ing 3 longitudinal stripes, median stripe
pattern can vary from tergites 2-6 having a very narrow, dark brown, sublateral stripes
pale inverted "V" formed by hair, to a brown and broad. Scutellum dark brown
dark, well defined, integumental inverted basally, brown apically, yellow pilose.
"V" pattern that includes Vs or more of the Pleuron yellow-gray tomentose. Fore coxa
tergite. In all these cases, the characteristic light brown tomentose, mid and hind coxa
wing pattern described above and the in- dark brown tomentose, femur, tibia and tar-
flated scape and pedicel will define C. at- sus light brown, femur and tibia bearing
lanticus. yellow hairs, except apices of tibia bearing
mixed yellow and black hairs, tarsus bear-
Chrysops brunneus Hine ing black hairs. Wing pattern distinct, apical
(Figs. 5, 14, 23) spot broad, extending around wing margin
Chrysops brunneus Hine 1903: 34. Syn- to crossband, leaving narrow hyaline band
types female and male: Sandusky, Ohio, along outer margin of crossband that does
9 S (OSUC), 1 $ (BMNH); Goodwin not reach vein R2f3, outer margin of cross-
1976: 343, description of larva and pupa. band straight or sinuous, 5th posterior cell
— infuscated, cells br and bm % and Vi their
Diagnosis. Robust species, length 8-10 length respectively. Halter with dark brown
mm. Antenna with scape and pedicel swol- stalk and light brown knob. Abdomen uni-
len, flagellum distinctly shorter than com- formly brown, lacking dark integumental
bined length of scape and pedicel. Frontal markings, tergite 1 with black hair medi-
callus strongly inflated, width twice height. anly, yellow hair laterally, tergites 2-4 pre-
Wing with apical spot extensive, reaching dominantly black-haired, except for yellow
around margin of wing to crossband and hairs on posterior margin that expand me-
enclosing hyaline crescent. Cells br and bm dianly into indistinct yellow-haired trian-
% and Vi infuscated basally. Abdominal pat- gles, tergites 5-7 with mixed black and yel-
tern indisti—nct. low hairs forming no distinct pattern. Ster-
Female. Yellowish brown. Scape and nites 1-5 light brown, sternites 3-5 with
pedicel distinctly swollen, scape twice as progressively larger median and lateral
long as broad, light brown, black setose, brown integumental spots, 6-7 dark brown,
basal flagellomere yellow basally, dark all sternites with mixed black and yellow
brown apically, apical flagellomeres black, hairs. —
flagellum distinctly shorter than scape and Male. Resembles female except for the
pedicel combined, antennal ratio 18:12:25. usual sexual differences and the following
Frontoclypeus glossy yellow, eye margins characteristics. Length 8.2-10 mm, scape
bearing yellow tomentum that extends me- and pedicel slightly more inflated than in
dianly beneath tentorial pits to frontocly- female, with longer, finer black hair, fron-
peal suture. Maxillary palp light brown toclypeus with yellow tomentose triangle at
with sparse black hairs. Frons yellow to- vertex, cheeks yellow pollinose. Long yel-
mentose with scattered yellow hairs, con- low hairs scattered over mesoscutum, scu-
vergent above, height 1.3 times width at tellum, and abdomen. —
base. Frontal callus elliptical, distinctly nar- Material examined. 502 9 and 14 S
— —
182 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
11
J"M:\
Figs. 10-12. Distributions. 10, Chiysops reiclierti. 11, C. sandyi. 12, C. tiiinidicumis.
were examined from the following collec- found in marshes near lakes such as Lake
tions: AMNH, CASC, CNCI, CUCC, Michigan, Lake Erie and Lake Ontario.
CUIC, FMNH, FSCA, INHS, OSUC, Discussion. Chrysops brunneus is very
TAMU, UGCA, UNHC, USNM. distinctive and can be separated from other
—
Distribution. New York to Florida, species of the C flavidus group by its
west to Texas, and north to Michigan and strongly inflated scape and pedicel that
southern Ontario. It is not found in the Ap- combined are longer than the flagellum, and
palachian Highlands and surrounding ter- by its reduced hyaline triangle appearing as
rain. I have examined specimens from: AL, c' crescent-shaped area between the cross-
AR, DE, FL, GA, IL, IN, KS, KY, LA, MD, band and broad apical spot. The smoky
MI, MS, NJ, NY, OH, OK, PA, SC, TN, wing pattern of C. brunneus and its pres-
TX, and VA. It is also known from lA, MO, ence in a saline environment are similar to
NC, and Ontario, Canada. that of C. atlanticus, but is easily separated
Biology. Chrysops brunneus is associ- by those characters noted above.
ated with both fresh and salt water habitats. The only variation observed in this spe-
Goodwin (1976) reared a larva of this spe- cies was the abdominal pattern that has ter-
cies collected from a salt marsh in Mc- gites 2-3 with small, median, black dashes
Clellanville, SC. Adults are commonly on the integument in approximately 5% of
VOLUME 101, NUMBER 1 183
atlanticus brunneus ce/atus
13 14 15
pudicus
dixianus flavidus
18
17
16
reicherti sandyi
tumidicornis
19 20
21
Figs. 13-21. Female antennae. 13, Clvysops atlanticus. 14, C hnmneus. 15, C. celatus. 16, C. dixianus.
C C C
17, C.flavidus. 18, C. pudicus. 19, reicherti. 20, sandyi. 21, tumidicornis.
the specimens examined. Ordinarily the ab- neath tentorial pits to frontoclypeal suture.
dominal pattern is indistinct with only some Maxillary palp and labrum yellow. Frons pre-
dark shadowing from dark hairs. dominantly yellow-gray tomentose with scat-
tered yellow hair, slightly convergent above,
Chrysops celatus Pechuman height 1.5 times width at base. Frontal callus
(Figs. 6, 15, 24) spade shaped, bulbous, yellow brown, width
Chrysopsflavidus celatus Pechuman 1949: and height subequal. Vertex gray tomentose,
82-83. Holotype female: Medford Lakes, except glossy brown integument associated
New Jersey (CUIC); Pechuman 1957: 30, with each ocellus which extends narrowly to
description of male. upper margin of frontal callus. Mesoscutum
Chrysops celatus: Teskey 1969: 34, de- greenish-gray iridescent, except lateral mar-
scription of larva and pupa. gins yellow tomentose, bearing 3 black lon-
— gitudinal stripes, the median one narrow
Diagnosis. Black and yellow, length 8- and flanked with gray. Scutellum black ba-
9.8 mm. Scape and pedicel not swollen, fla- sally. Pleuron yellow tomentose. Legs
gellum V3 longer than scape and pedicel mostly yellow, fore leg with tarsus and api-
combined. Frontal callus spade shaped, cal portion of tibia dark brown with black
width and height subequal. Mesoscutum hair, mid and hind coxa brown, tarsus with
greenish gray iridescent with black longi- black hairs. Wing pattern with broad apical
tudinal stripes. Cells br and bm Vi and '/, spot entering apical halfof2nd submarginal
infuscated—basally. cell, apex of hyaline triangle not reaching
Female. Scape and pedicel not swollen, vein R2+3, outer margin ofbrown crossband
light brown, black setose, basal flagellomere sinuous, 5th posterior cell infuscated basal-
light brown basally, black apically, apical fla- ly, hyaline apically, cells br and bm V2 and
gellomeres black, 1.3 times length of basal infuscated basally. Halter brown. Tergites
'/s
flagellomere, antennal ratio 15:10:34. Fron- 1-2 yellow brown, tergite 2 with darker
toclypeus glossy yellow, eye margins bearing median integumental marking appearing as
yellow tomentum that extends medianly be- an inverted "V" set over median yellow-
184 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
brown triangle, tergites 3-4 predominantly Peak flight time over its entire range is in
brown except for lighter posterior margin June. Although it is a common species, it
that expands medianly into light brown pol- is not abundant enough to be considered a
linose triangle, remaining tergites with an- pest. —
terior % brown, posterior V3 yellow-brown. Discussion. Pechuman (1949) first de-
Stemites yellow-brown pollinose with ster- scribed C. celatus as a subspecies of C.
nites 3-7 bearing narrow yellow pollinose flovidus, and it was so treated until Teskey
line along the posterior margin, stemites 5- (1969) found the larvae and pupae of the
7 predom—inantly brown. two subspecies to be specifically distinct.
C
Male. Similar to female except for the The adult of celatus most closely resem-
usual sexual differences and following bles C.flavidus and C. reicherti, and can be
characters. Length 6.5-7.5 mm. Pedicel separated by its greenish-grey mesoscutum
only slightly shorter than scape, with finer, and the longer, more slender antennae. The
longer black hairs, length of basal flagel- sinuous outer margin ofthe crossband in C.
lomere and combined apical flagellomeres celatus is similar to that of C. reicherti, but
subequal. Apical spot reaches posteriorhalf in C. flavidus this margin is either straight
of 2nd submarginal cell and then fades or concave. The larva resembles C.flavidus
along hind margin, cells br and bm % and (Goodwin 1976) and C. dixianus (Teskey
V2 infuscated basally. First tergite with dark 1969).
spot under scutellum or entirely dark. Fifty The characters used to define C. celatus
percent of males examined with abdominal are consistent, in most cases, but there is
pattern of yellow and black with a black some variation in the color pattern of the
scutellum. abdomen and wings, and in the color ofthe
—
Material examined. 574 9, 30 6, ex- scutellum. The abdominal pattern on ter-
amined from the following museums: gites 2-3 may vary from a black inverted
AMNH, CASC, CNCI, CUCC, CUIC, "V" on the integument to lighter markings
FSCA, INHS, TAMU, UGCA, UNHC, of dark hairs only. The apical spot of the
USNM. wing may be extended and fade out along
—
Distribution. Massachusetts south to the hind margin of the wing, approaching a
Florida, west to Texas; disjunct population pattern much like that of C. reicherti. Spec-
in Michigan, southern Ontario, and north- imens with this wing pattern tend to be
ern Ohio, Illinois, and Indiana. I have ex- more robust and have a more darkly infus-
amined specimens from the following cated wing. The scutellum, which is usually
states: AL, CT, DE, FL, GA, IN, KY, LA, dark basally and reddish apically, is either
MA, MD, MI, MS, NC, NH, NJ, NY, SC, wholly dark or reddish.
TN, TX, and VA. L. L. Pechuman has re-
corded specimens from WV, and Ontario, Chrysops dixianus Pechuman
Canada. (Figs. 7, 16, 25)
—
Biology. Teskey (1969), based his de- Chrysops dixianus Pechuman 1974: 185-
scription of the larva on 35 specimens. 187. Holotype female: Wedge Plantation,
They were collected from 3 sites with fresh, McClellanville, South Carolina (CUIC);
standing water: wet sand, organic soil, and Goodwin 1976: 345-347, description of
around roots of aquatic vegetation. In 1972, larva and pupa.
Teskey also collected larvae from the edge —
of a slow-moving stream in Virginia (Pe- Diagnosis. Yellow and brown species,
chuman 1973). length 6-8.5 mm. Antenna not swollen, fla-
The flight period for Chrysops celatiis is gellum V3 longer than scape and pedicel
late May to September in its northern range, combined. Frons width at base subequal to
and from April to late October in the south. width at vertex. Hind coxa and femur dark