THE NEW WORLD GENUS CHROMOLEPIDA COLE (DIPTERA : THEREVIDAE : THEREVINAE)

28 Pages·1995·12.1 MB·

by  D W Webb

PROC. ENTOMOL. SOC. WASH.
97(1), 1995, pp. 197-224
THE NEW WORLD GENUS CHROMOLEPIDA COLE
(DIPTERA: THEREVIDAE: THEREVINAE)
Donald W. Webb and Michael E. Irwin
Illinois Natural History Survey, 605 East Peabody Drive, Champaign, Illinois 61820.
Abstract.—^Xi^c\tsofthegenus ChwmolepidaColeareconfinedtowesternNorthAmer-
ican and northern South America. The species are revised, a phylogeny is hypothesized,
and a key to the species is provided. Two species from Mexico, Chwmolepida clavitibia
Webb and Irwin and C. nigra Webb and Irwin, are described as new to science.
Key Words: Diptera, stiletto flies, Therevidae, Chromolepida, NewWorldrevision, phy-
logeny, species keys, descriptions, distributions
This paper is the fifth ofa series (Webb mated data management system originally
and Irwin 1988, Webb and Irwin 1991a, b, designed by Rauch (1970).
c) revising the species ofthe genera treated To conserve space and include as much
in the monograph ofthe Nearctic genera of information as possible about each speci-
Therevidae. A key to the species o{Chrom- men, a format adopted from Irwin (1983)
olepida Cole is provided along with species is used in the "Specimens Examined" sec-
descriptions and distributions. tionofeach species. Manyoftheterms used
The morphological terminology used for there were defined by Stuckenberg and Ir-
the male terminalia was originally defined win (1973). In the presentation ofrepetitive
and described by Lyneborg (1968) and sub- locality data, a semicolon terminates one
sequently modified by Lyneborg (1972, series of specimens and signals the begin-
1976, 1978) and Irwin (1977a, b). The fe- ning ofthe next, thus, data not repeated in
male terminalia terminology was defined a series are the same as those ofpreceding
and described by Irwin (1976). Other mor- series.
phological features are described with ter-
Phylogenetic Relationships
minologysetoutinthe"ManualofNearctic
Diptera" (McAlpine 1981). The range for The genus Chromolepida belongs to the
each setal count is followed by the mode. Cyclotelus group of therevids, along with
Setal counts were taken from the left side CyclotelusWalker, OzodiceromyaBigot, and
of the specimen and from the entire pos- anundescribedgenusfromChile. Thisgroup
terior margin ofthe scutellum. ischaracterized by ratherbulbousgonocox-
Each specimen was assigned a unique ites. The black, glossy calli on the face ven-
THEREVIDAE/M. E. IRWIN/SPECI- traltotheantennal basesandthe appressed,
MEN number. This number is used to as- iridescent, silver green scales on the thorax
sociate the ecological and label data with a and abdomen separate Chromolepida as a
given specimen, and when referred to here- monophyletic genus within this group.
in, is printed in italics. The data are in- The cladogram (Fig. 1) represents the re-
tended to be incorporated into an auto- lationship we hypothesize for the five spe-
198 PROCEEDINGS OFTHE ENTOMOLOGICALSOCIETY OFWASHINGTON
.
VOLUME97, NUMBER 1 199
Table 1. Characterstates for Chromolepida.
Plesiomorphic Apomorphic
1 Female frontal setae present Female frontal setae absent
2. Male gonostylus simple Malegonostylus with lateral projection
3. Male dorsal apodeme truncate or slightly Male dorsal apodemedeeplyemarginate anteriorly
emarginate anteriorly
4. Male ventral apodeme truncate or slightly Male ventral apodeme pointed, extendedanteriorly
emarginate anteriorly
5. Endophallus simple Endophallusrecurved
curved than all other species ofChromole- separated from C. mexicana and is cur-
pida. This species currently ranges from rently restricted to the southern tip ofBaja
C
California to southern Washington, east to CaliforniadeSur, with mexicanaranging
Idaho, northern Utah, and Nevada. from northern Mexico to southern Califor-
Chromolepida pruinosa formed a south- nia, Arizona, New Mexico, western Texas,
C
em, neotropical clade separated from and southern Colorado, but not sympatric
C
bella by the possession ofa lateral projec- with bella.
tion on the male gonostylus and from C. Chromolepida may be separated from
nigra, C. clavitibia, and C. mexicana in re- other Nearctic therevids by using the keys
tainingthemoreprimitivecharacteristicsof to the genera ofNearctic Therevidae in Ir-
the male dorsal and ventral apodemes of win and Lyneborg(1981a, b). No keyto the
the aedeagus. It currently ranges from Guy- genera ofNeotropical Therevidae is avail-
ana to Colombia, north to Nicaragua. able at this time; however, all species of
C C
Chromolepida nigra, clavitibia, and Chromolepida have a pair of shiny, black,
mexicana form a clade defined by the male raised calli on the upper face below the an-
dorsalapodemeoftheaedeagusbeingdeep- tennal bases, which is unique to species of
ly emarginate anteriorly and the anterior this genus.
apodeme ofthe aedeagus beingpointed and
Chromolepida Cole
extended anteriorly. These species are cen-
tered in Mexico and the southwestern Unit- Chromolepida Cole (1923: 23). Type spe-
ed States with C. nigra found in southern cies: Psilocephala pruinosa Coquillett
Mexico,butnotsympatricwithC.pruinosa. (1904: 91) by original designation.
Chromolepida clavitibia and C. mexicana Derivation ofname.—c/zrama (Greek) =
form the final clade based on the presence color; lepido (Greek) = scale.
offrontal setae in the females ofboth spe- Diagnosis.—Chromolepida is a member
cies. Chromolepida clavitibia apparently
ofthe Cyclotelus group oftherevid genera.
Beyond Chromolepida, this group includes
Table 2. Character matrix for Chromolepida. CyclotelusWalker, OzodiceromyaBigot,and
an undescribed genus from Chile. Species
Charactermatnx in this group ofgenera can be characterized
1112 by the following: middle coxae without se-
Chromolepidabella 212 tae on posterior surface; male gonocoxites
Chromolepidaclavitibia 12 2 2 2 often strongly fused ventrally, forming a
Chromolepida mexicana 2 2 1 rather compact capsule; dorsal apodeme of
Chromolepida nigra 2 2 2112 11 male aedeagus weakly to stronglyjoined to
Chromolepidapruinosa 2 2
internaldorsalportionofgonocoxite(=par-
200 PROCEEDINGS OFTHE ENTOMOLOGICALSOCIETY OFWASHINGTON
Figs. 2-n. Chromolepida bella {9177, 9179) 2. Male tergite 8, epandrium, cercus, and hypoproct, dorsal
view. 3. Male stemite 8, gonocoxites and gonostylus, ventral view. 4. Malegonocoxitesand gonostylus, dorsal
view. 5. Malegonocoxite, lateral view. 6. Male aedeagus, dorsal view. 7. Maleaedeagus, ventral view. 8. Male
aedeagus,lateralview. 9. Femaleterminalia,dorsalview. 10. Femaleterminalia,ventralview. 11. Femalefurca,
dorsal view. Scale = 0.1 mm, unlessotherwise indicated.
ameral process); male hypandiium small or pressed iridescent silver green scales in ad-
absent; male gonocoxites usually strongly dition to normal setae.
fused with lateral margins of epandrium; Small to medium-sized flies.
posterior parameral processes composed of Description ofmale and female.—Head:
pairofnonarticulatedprojections; andmale Eyes ofmale holoptic, ommatidia on ven-
distiphallus of aedeagus often curved, ex- tral third smaller; eyes offemale dichoptic,
tending posteroventrally beyond gonocox- all ommatidia ofsimilar size; antenna (Fig.
ites. Chromolepida is separated from the 42), length 0.9-1.7 times head length; scape
othergenera ofthe Cyclotelusgroup in hav- cylindrical; pedicel cylindrical to ovate; fla-
inga pair ofshiny, black, raised calli on the gellum awl-shaped, tapered apically; style
facejust below the antennal bases, and the subapical, two-segmented, including min-
thorax and abdomen clothed with ap- ute apical spine; frons in female (Fig. 52)
VOLUME 97, NUMBER 1 201
Figs. 12-21. Chromolepida clavitibia {8812, 8805) 12. Male tergite 8, epandrium, cercus, and hypoproct,
dorsalview. 13. Malestemite8,gonocoxitesandgonostylus,ventralview. 14. Malegonocoxitesandgonostylus,
dorsalview. 15. Malegonocoxite,lateralview. 16. Maleaedeagus,dorsalview. 17. Maleaedeagus,ventralview.
18. Male aedeagus, lateral view. 19. Female terminalia, dorsal view. 20. Female terminalia, ventral view. 21.
Female furca, dorsal view. Scale = 0.1 mm, unless otherwise indicated.
broad, lateral margins convergent dorsally; setae white, filiform and silver green scale-
frontalcalliglossy,withdistinctareaofblack like, ventral projection of gena with con-
pile dorsolateral to antennal bases; parafa- centration of short, black, filiform setae.
cial broad with enlarged, glossy parafacial Macrosetaethick, filiform, moderatelylong,
calli; maxillary palpus one-segmented (Fig. scattered on apex ofscape.
43), cylindrical to slightly clavate, rounded Thorax: Macrosetae: np 3-4, sa 1, pa 1,
apically. Setae of two types (filiform, and dc 0, sc 4. Postpronotal lobe concolorous
appressed, iridescent, silvergreenscale-like), with thorax. Vittae indistinct. Setae of 2
scattered filiform on female frons; short, fi- types: filiform,onprostemum, mesonotum,
liform on antenna, abundant, filiform on propleuron, anepistemum, and dorsal third
maxillarypalpus, absentoneyes, parafacial, ofkatepistemum,andappressed, iridescent,
clypeus and generally on male frons. Genal silver-green scale-like on mesonotum, pro-
202 PROCEEDINGS OFTHE ENTOMOLOGICALSOCIETY OFWASHINGTON
27 28
Figs. 22-3L Chromolepida mexicana {8814, 9025) 22. Male tergite 8, epandrium, cercus, and hypoproct,
dorsalview. 23.Malestemite8,gonocoxitesandgonostylus,ventralview. 24. Malegonocoxitesandgonostylus,
dorsalview. 24. Malegonocoxite,lateralview. 26. Maleaedeagus,dorsalview. 27. Maleaedeagus,ventralview.
28. Male aedeagus, lateral view. 29. Female terminalia, dorsal view. 30. Female terminalia, ventral view. 31.
Female furca, dorsal view. Scale = 0.1 mm, unless otherwise indicated.
pleuron, anepistemum and dorsal third of form, and appressed, iridescent, silver-green
katepistemum, absent on remainingpleural scale-like, on anterior halfoffore and mid-
sclerites. Wing (Fig. 44) hyaline to opaque, dle coxae and over entire hind coxa, over
often patterned; veinsgenerally palebrown; entire femora, filiform on tibiae. Macrose-
pterostigma indistinctto brown; setulae ab- taedarkbrown, apical, 2on foreandmiddle
sent; length of R4 0.8-1.3 times R5; length coxae, 3 on hind coxa.
ofcell r4 1.7-4.0 timeswidth; veins M,, M^, Abdomen: Rather narrow, gradually ta-
and M3 originate separately from apical peringfrom base to apex, male dorsum flat-
margin of discal cell; cell m^ open; discal tened, female dorsum convex. Setae fili-
cell acute basally; cell cup closed with short form, appressed, iridescent, silver green
petiole; m-cu/r-m subequal. Legs. Coxae scale-like or lanceolate. Male terminalia
moderately long. Setae of two types: fili- (Figs. 2-8, 12-18, 22-28, 32-38, 42-51).
VOLUME NUMBER
97, 1 203
Figs. 32^1. Chromolepida nigra{8815, 9239) 32. Maletergite 8, epandrium,cercus,andhypoproct,dorsal
view. 33. Malestemite8,gonocoxitesandgonostylus,ventralview. 34. Malegonocoxitesandgonostylus,dorsal
view. 35. Male gonocoxite, lateral view. 36. Male aedeagus, dorsal view. 37. Male aedeagus, ventral view. 38.
Maleaedeagus,lateralview. 39. Femaleterminalia,dorsalview.40.Femaleterminalia,ventralview.41.Female
furca, dorsal view. Scale = 0.1 mm, unless otherwise indicated.
Tergite 8 large, aboutaswideasepandrium, patch of short setae. Parameral apodeme
posterior deeply emarginate. Sternite 8 reduced. Gonostyluselongate, withorwith-
somewhat reduced, posterior emarginate. out lateral projection. Aedeagus attached to
Epandrium about two-thirds as long me- parameres and gonocoxites; a long, weak,
diallyaswide, posterolateralcomersround- membranous bridge stretching from distal
ed; cercus free, well sclerotized, ending be- comers ofdorsal apodeme to midsection of
foreorslightlybeyondhypoproct; hypoproct paramere and a stronger attachment be-
attachedtomembranoussubepandrialplate, tween ventral lobesofgonocoxitesand ven-
whichextendsanteriorlyandattachestoan- tral surface ofaedeagus; distiphallus scler-
terior margin ofaedeagal dorsal apodeme. otized, variable; ventral apodeme extends
Hypandriumgreatly reduced, narrow. Gon- parallel to dorsal apodeme, anterior margin
ocoxitebulbous, sidesbroad in lateral view; variable; ejaculatoryapodemeaboutaslong
in ventral view, gonocoxite with medial as ventral apodeme, slender. Female ter-
. . .
204 PROCEEDINGS OFTHE ENTOMOLOGICAL SOCIETY OFWASHINGTON
minalia (Figs. 9-11, 19-21, 29-31, 39-41, to black apical band; male distiphallus short
53-55).Tergite8 subrectangular,longerthan to moderately long, ifrecurved, only slightly
wide, with broadly concave posterior mar- (Figs. 18, 28, 38, 51); male gonostylus with
lateralprojection(Figs. 14,24, 34,47);frontal
gin; setae black, elongate, scattered. Tergite setaeblack 5
9+10 fused, with strong acanthophorites. 5. Costalandsubcostalcellsofwingdarkyellow;
Cercus triangular, membranous, with nu- male distiphallus short, sinuate (Fig. 51) ...
merous, fine, short setae projecting poste- pruinosa (Coquillett) (males and females)
Costalandsubcostalcellsofwinghyaline;dis-
riorly. Stemite 8 large, longer than wide;
tiphalluselongate,bentatrightangletoplane
posterior emarginate; setae black, elongate, ofaedeagus(Figs. 28, 38) 6
scattered. Stemite 9 greatly modified, in- 6 Gonocoxiteinlateralview(Fig.25)withdistal
vaginated above stemite 8 to form internal halfbroad; length offore femur to length of
sclerotized furca which is closed anteriorly; scape 2.4 ± 0.2; length offoretibia to length
ofscape 2.5 ± 0.2; length ofhind femur to
ventral surface offurca covered with lightly length ofscape 3.5 ± 0.4
sclerotized membrane. Stemite 10 mem- mexicana Cole (males)
branous, subtriangular with short, thick se- Gonocoxiteinlateralview(Fig.35)withdistal
tae. halfreduced, tapered apically; length offore
Immature stages.—Unknown. femurto length ofscape 1.7 ± 0.2; length of
foretibia to length ofscape 1.8 ± 0.2; length
Biology.—Adults of Chromolepida have ofhind femurto length ofscape 2.4 ± 0.3
. .
been collected from flowers ofa variety of nigra Webband Irwin, n. sp. (males)
plants, a reseeded range, a fen area, oak-
chapparal habitats, and coastal dunes.
Distribution (Figs. 56-5%).-Chromolepi- Chromolepida bella Cole
da has been collected from South America Chromolepida bella Cole (1923: 24): Cole
(Guyana, Venezuela, Colombia) and in (1965: 350); Irwin and Lyneborg (1981a:
NorthAmericafrom Costa Ricatothe state 260).
ofWashington and eastward to Utah, Col- =
orado and westem Texas. Derivation of ndirwt.—bellus (Latin)
beautiful.
Key to Species of Chromolepida Diagnosis.—Females of Chromolepida
C C
bella, like nigra and pruinosa, lack
1 HHaalltteerrydealrlkobwrown 42 frontal setae. The species is separated from
2. Femoradarkreddishbrown to black 3 C. nigra in havingthe wing membrane pale
- Femoradarkyellow mexicana Cole (females) yellow, concolorous; the anterior margin of
. .
3. Foretibiadistinctlyclavate the dorsal apodeme of the male aedeagus
. . .clavitibiaWebband Irwin, n. sp. (malesand fe- truncate; and the females have yellow hal-
males)
Foretibia cylindrical teres and femora. Chromolepida bella, un-
nigra Webb and Irwin, n. sp. (females) like C. pruinosa, has pale yellow, concol-
4. Wing membrane without apical band; male orouswingmembranes; the malegonostylus
distiphalluselongate,distinctlyrecurved(Fig. lacks a lateral projection; and the male dis-
8); male gonostylus lacking lateral projection tiphallus is elongate and sinuate.
(Fig. 4); male frontal setaeabsent
Redescriptionofholotypemale(9777).—
bella Cole (malesand females)
Wingmembrane(Fig. 44)with smokybrown Body length 4.0 mm.
Figs.42-55. Chromolepidapruinosa{9218,8316)42. Maleantenna,lateralview.43. Malemaxillarypalpus,
lateralview. 44. Malewing,dorsal view. 45. Maletergite 8, epandrium, cercus, andhypoproct,dorsalview. 46.
Male stemite 8, gonocoxites and gonostylus, ventral view. 47. Male gonocoxites and gonostylus, dorsal view
(aedeagal complex removed). 48. Male gonocoxite, lateral view. 49. Male aedeagus, dorsal view. 50. Male
205
VOLUME NUMBER
97, 1
aeueasus, ve„.ra, v,ew. 5r Ma,e aedeasus, ,a-e.U.^. 5. F™^^^^^^^^^^
206 PROCEEDINGS OFTHE ENTOMOLOGICALSOCIETYOFWASHINGTON
Head: Length 0.8 mm. Ocellar tubercle
dark reddish brown, silver pruinose; setae
dark reddish brown. Eyes dull reddish
brown; medial margin rounded. Frons dark
reddishbrown, glossy, with lateral silverpile
and black dorsal pile, dorsal pile becoming
silverdorsally. Antennadarkreddishbrown,
pruinose; setaedark reddish brown; macro-
setaedarkbrown;lengthofantenna 1.4times
head length; length ofscape 0.75 mm, 9.3
times width, 4.4 times length of pedicel;
lengthofpedicelO.il mm, 1.1 times width;
length of flagellum 0.34 mm, 3.4 times
width, 0.4 times length of scape; length of
basal stylomere 0.05 mm. Parafacial dark
reddish brown, glossy with silver pile along
lateral margins. Maxillary palpus pale
brown; length 0.28 mm, 2.8 times width;
setae pale yellow.
Thorax: Macrosetae: np 3. Dark reddish
brown, pruinose. Postpronotal setae white,
filiform and scale-like. Prosternal setae
white. Pleuradarkreddishbrown, pruinose,
anepistemum and ventral half of katepi-
stemum glossy; setae white, filiform, scat-
tered on propleuron and dorsal halfofkat-
epistemum, paleyellow, filiform, overentire
anepistemum, scale-like over propleuron,
anepistemum, and dorsal half of katepi- Fig. 56. Thedistribution ofChromolepidabellain
stemum. Scutellum darkreddish brown; se- the western United States.
tae white, filiform, and scale-like. Latero-
tergite dark reddish brown, pminose; setae projection. Dorsal apodeme of aedeagus
dark white to pale yellow, filiform. Wing. broad anteriorly, wider than ventral apo-
Length 3.2 mm, 2.7 times width; pale yel- deme, anterior slightly emarginate; disti-
low, opaque; pterostigma indistinct. Halter phallus elongate, sinuate.
dark yellow, stalk darker. Legs. Coxae dark Variation in males: Body measurements
reddish brown, pruinose. Femora dark yel- for males are provided in Table 3. Consid-
lowish brown. Fore tibiae dark reddish erable variation in coloration was noted be-
brown, middle and hind tibia dark yellow- tween the holotype and most males ofthis
ish brown. Tarsi dark brown. Coxal and species. Specimensinthe San Franciscoarea
femoral setae white, filiform and scale-like; and from Inglenook Fen appeared to be
tibial setae dark reddish brown. smaller and more slender in size than spec-
Abdomen: Dark reddish brown; setae imensinland from thecoastal dune habitats
white, filiform, moreabundant laterallythan where the holotype was collected. Head.
dorsally, and white, appressed, lanceolate, Antenna reddish brown, pruinose, paler on
more abundant along posterior margins. basal half of scape; setae reddish brown.
Terminalia (Figs. 2-8). Dark yellow. Ster- Maxillarypalpusdarkreddishbrown. Inone
nite 8 moderatelyreduced, posteriormargin specimen {9045), a few frontal setae were
slightly concave. Gonostylus lacks lateral noted at base ofantenna. Wing. Membrane