DASTPOGONINAE 



ROBBER FLIES OF THE WORLD 



205 



Genus Coleomyia Wilcox and Martin 



Figubes 130, 517, 1106, 1115, 1845, 1869, 1955 



Coleomyia Wilcox and Martin, Bull. Brooklyn Ent. Soc, vol. 

 30, p. 205, 1935. Type of genus : Aletapogon setigerum Cole, 

 in Cole and Lovett, 1919, by original designation. 



Small flies of bare aspect and extremely reduced pile, 

 which is black or dull in color with some pollen. They 

 are most readily distinguished by the short face, the 

 short antenna and the rather scattered, exceptionally 

 stout bristles of the face on which pile is almost lacking. 

 Protibial apex without spine. Scutellum as in Nan- 

 nocyrtopogon Wilcox and Martin, apilose, the margin 

 with conspicuously stout bristles. Male wings some- 

 times bicolored. Length 8 to 12 mm. 



Head, lateral aspect : The head is of medium length, 

 face short near the antenna, becoming a little more 

 prominent below due to the recession of the eye. The 

 face is not quite plane and more distinctly rounded just 

 above the epistoma. The subepistomal area small, con- 

 cave and distinctly horizontal. Occiput moderately 

 developed, except at the vertex. There is a gentle pos- 

 teroventral recession of the eye beginning at the middle 

 of the head. Occipital pile is fine, moderately long, 

 but not abundant ; bristles begin near the upper third, 

 the lower ones weak, the upper elements quite stout. 

 There are no distinct postvertical bristles, although the 

 last 2 are slightly medial to the eye. Proboscis is short, 

 and quite robust, but compressed to a blunt point on the 

 outer fourth and not extended beyond the face. The 

 palpus is small, of two segments, the first segment ex- 

 cavated, the second short and cylindrical, with an apical 

 bristles. The antenna is attached at the middle of the 

 head and rather short, not as long as the head. Both 

 first and second segments beadlike, the first with 1, the 

 second with 3 exceptionally stout, long, ventral bristles. 

 Third segment very little if any wider than the second 

 segment, barely narrowed at base, a little more strongly 

 at the apex, with a conical spine-tipped microsegment. 



Head, anterior aspect : The head is not as wide as the 

 thorax; the face below antenna about one-fourth the 

 head width, slightly wider below, densely micropubes- 

 cent; pile is almost absent on the face, such pile as 

 is present is bristly, and beginning shortly beneath 

 the antenna are long, scattered, very stout, blunt, black 

 bristles. Front divergent, convergent again at the ver- 

 tex, with 3 shallow central grooves; surface pollinose 

 near the eye margin, with a longitudinal row of 6 

 stout bristles and a submedial patch of 4 setae. Vertex 

 only moderately excavated, with slanting lateral sides, 

 very large ocellarium, also with slanting sides, bearing 

 between the ocelli 3 pairs and behind the ocelli 2 pairs 

 of long, conspicuous, blunt bristles. Anterior eye facets 

 moderately enlarged. 



Thorax: The thorax is pollinose, with very little pile 

 which consists of a few, fine, scattered, anterior and 

 also supraalar setae. There are only 1 or 2 minute 



acrostical bristles but there are long, stout, conspicuous 

 dorsocentral bristles anteriorly as well as posteriorly 

 consisting of 6 or 7 pairs. Lateral complement of 

 stout, long bristles comprises 2 humeral, 1 posthunieral, 

 2 notopleural, 1 supraalar, 2 postalar, and 1 to 2 pairs 

 of scutellar bristles. Pronotal collar with at most 1 

 or 2 slender bristles, usually only fine pile. Lateral 

 pronotum with 1 or 2 stout bristles, a few fine hairs, 

 and cervical sclerite with dense, fine pile. Prosternum 

 dissociated. Metapleuron with 4 or 5 similar bristles 

 in a vertical row; remainder of pleuron without pile, 

 but largely pollinose, but with bare areas below. 

 Lateral and ventral metasternum with pile; postmeta- 

 coxal area membranous. 



Legs : The legs are stout ; all the femora are very 

 slightly swollen through the middle but not con- 

 spicuously, their pile appressed setate, dense on the 

 upper half, almost bare below. All femora ventrally 

 with a few quite long bristly hairs; tibial bristles 

 prominent, femoral bristles quite short. Hind femur 

 with 7 or 8 lateral bristles, 1 or 2 of which may be 

 stout, the apex with 1 or 2 on each side. Middle femur 

 with a few short bristles anteriorly, especially antero- 

 ventrally. Anterior femur with 5 concentrated on the 

 outer half behind. Posterior tibia with 5 dorsomedial, 

 some minute medial bristles, and 5 lateral bristles, the 

 same number of ventral bristles. Midtibial antero- 

 dorsal and ventral bristles unusually long, 5 in the 

 former row, 4 in the latter, and 5 or 6 bristles each in 

 the anteroventral, posterodorsal, and posterior rows. 

 Anterior tibia with 7 short posterior bristles, the same 

 number of posterodorsal, 9 anterior dorsal and 4 long, 

 ventral bristles. Apex without spine. Claws slender, 

 sharp ; pulvilli and empodium well developed. 



Wings: The wings are slender, all posterior cells 

 widely open, fourth very slightly narrowed, the rec- 

 tangular anterior crossvein enters the discal cell near 

 the middle. Middle end of the second basal cell long. 

 End veins of discal cell of equal length. Anal cell 

 open; alula of medium length; ambient vein complete. 

 Abdomen: The abdomen is comparatively robust at 

 the base, strongly tapered in the females, less so in the 

 males. The pile is appressed setate and quite scanty. 

 Segments dully shining, bare, with posterior pollinose 

 fasciae or pairs of spots. First tergite with 2 to 4 stout 

 bristles laterally. Males with seven tergites, the last is 

 half the length of the sixth. Females with eight ter- 

 gites, the last is reduced to half. Male terminal ia ro- 

 tate one-half, small and inconspicuous. The epandrium 

 is cleft but overlapping at the base, gonopod broad at 

 the base with a distal lobe. Hypandrium very short. 

 Genital cavity open. Females with 7 or 8 pairs of short, 

 spoonlike spines on the acanthophorites. 



Distribution: Nearctic: Coleomyia alticola James 

 (1941) ; hinei Wilcox and Martin (1935) ; rainieri Wil- 

 cox and Martin (1935) ; sculleni Wilcox and Martin 

 (1935) : setigerum Cole (1919). 



