DASYPOGONINAE 



ROBBER FLIES OF THE WORLD 



179 



hairs. Scutellar margin with 3 or 4 pairs of exception- 

 ally fine, long hairs. Scutellum convex, moderately 

 thick, the disc apparently -without pile or pubescence, 

 except for a few very fine, scattered hairs laterally. 

 Propleuron with a dense tuft of fine, quite long, 

 crinkled pile ventrally and laterally but oidy short, 

 fine hair dorsally on the collar. Sternopleuron with 

 similar pile; long, abundant pile present posterodor- 

 sally on the mesopleuron; pteropleuron apilose, the 

 hypopleuron with a few scattered, long hairs. Meta- 

 pleuron with a vertical band of exceptionally long, 

 crinkled pile which becomes stiff and bristly towards 

 the base. 



Legs: The anterior and middle femora are slender; 

 the hind femur is stout, its tibia is enormously swol- 

 len distally, but with the base slender. The hind basi- 

 tarsus is also enormously swollen, the remaining 

 segments progressively smaller. Dorsal pile of the fe- 

 mora short, appressed and setate. The following bris- 

 tles are present in the type of genus : the ventrolateral 

 margin of the hind femur with 8 to 10 bristly hairs, 

 ventromedial margin likewise with some slender, bris- 

 tly hairs. Hind tibia with 7 moderately long, slender, 

 dorsomedial bristles and 5 or G somewhat shorter dor- 

 solateral bristles ; the lower half of the lateral surface 

 and the ventral and medial surfaces have dense, ap- 

 pressed setae; the apex bears numerous fine bristles, 1 

 dorsomedial, 3 or 4 medial, 1 dorsolateral, 2 lateral, 

 and 6 ventral. Middle femur with long, fine, stiff hair 

 ventrally. Middle tibia with long, basally stout, 

 oblique, finely pointed bristles, of which there are 5 

 anterodorsol, 3 ventral, inclined anteriorly, and 12 to 

 14 long, pale, posterior bristles ; the dorsal surface with 

 a few, the ventral surface with more numerous, erect, 

 stiff hairs. Anterior femur with only long, fine hairs 

 ventrally. The anterior tibial bristles dorsally are 

 quite fine, short and weak; there are 7 or 8 anterodor- 

 sal and approximately a like number of posterodorsal, 

 with a posterior row of 4 or 5 slender bristles and 3 

 longer ventral bristles. Apex without spine and with 

 10 to 12 comparatively short bristles. All the ante- 

 rior 4 tarsi are slender, the basitarsus not quite as long 

 as the succeeding 3 segments. Tarsi end in slender, 

 sharp claws, long pulvilli, and a short empodium 

 strongly swollen at the base. 



Wings: The wings are broad; the marginal cell is 

 widely open; the anterior branch of the third vein 

 ends at the wing apex; the second submarginal cell is 

 slender, gradually though only moderately widened 

 apically and but little widened anteriorly at its base. 

 First posterior cell widely open, the fourth only 

 slightly narrowed; anal cell closed with a short stalk; 

 middle end vein of the second basal cell extremely short, 

 the anterior crossvein enters the discal cell at the 

 middle. The alula is short; ambient vein complete. 



Abdomen : The abdomen is comparatively wide and 

 distinctly flattened especially on the first three or four 

 tergites. Basally it is at least as wide as the mesonotum 

 or a little wider and tapers very slightly to the end of 

 the fifth tergite and somewhat more rapidly beyond. 



Sides of the tergites rather strongly though narrowly 

 rolled. Eight tergites are present, the seventh is three- 

 fourths as long as the sixth but the eighth is extremely 

 short. Pile of the abdomen scanty, more or less ap- 

 pressed and rather short except along the lateral mar- 

 gins where it is strikingly dense, long, bushy and 

 crinkled, continuing down over the rolled portions of 

 the tergites as a conspicuous, dense, ventral fringe. 

 First sternite without pile, the remaining sternites with 

 a few long, fine hairs. 



Distribution : Palaearctic : Pseudoholopogon chalcog- 

 aster Dufour (1850). 



Genus Eriopogon Loew 



Figttbes 91, 497, 1005, 1006, 1937 



Eriopogon Loew, Linnaea Entomologica, vol. 2, p. 487, 1847. 

 Type of genus: Dasypogon laniger Meigen, 1804, by 

 monotypy. 



Small flies distinguished by the open posterior cells 

 and the very dense, delicate, long, white pile present 

 over the head, thorax, legs and the sides of the abdomen. 

 Distinguished from Jothopogon Becker, which it 

 nearly resembles, by the laterally compressed abdomen, 

 the dense, long, discal pile of the scutellum and a short 

 hypopygium, scarcely longer than the last segment. 

 Hind coxa with a conical process. Length 10 to 11 mm. 



Head, lateral aspect : The face is comparatively short, 

 gently convex, with a slight elevation beginning im- 

 mediately beneath the antenna. Lower face recessive, 

 the whole profile very well hidden by dense, long, 

 bristly pile. The eye is of moderate length, strongly 

 convex anteriorly except in the middle where it tends 

 to be flattened, nearly plane posteriorly, except at the 

 immediate vertex; on the lower fifth it is strongly 

 anteroventrally recessive. Occiput thick, especially 

 medially, and particularly on the lower portion with 

 dense tufted or matted, long, fine pile which extends 

 outward to within a short distance of the eye margin 

 and is present throughout the length of the occiput; 

 bristles absent. The proboscis is short, laterally com- 

 pressed, and rather high, with nearly parallel sides 

 laterally, slightly tapered dorsally ; the apex is bluntly 

 rounded, a little more so on the dorsal aspect, and a 

 low medial ridge is present. The apex bears a few 

 stiff hairs continued ventrally over the outer third ; the 

 basal third bears numerous, long, fine hairs. Proboscis 

 directed horizontally forward and extending a short 

 distance beyond the face. Palpus minute, the first seg- 

 ment excavated, the second short and robust, a little 

 attenuate towards the apex and with a number of fine, 

 long hairs on all sides except medially. Antenna at- 

 tached at the upper fourth of the head ; the first two 

 segments are comparatively short; the first is robust, 

 convex dorsally and especially ventrally and bears 

 numerous long, bristly hairs ventrally and laterally; 

 second segment with 2 equally long bristly hairs ventro- 

 laterally and 3 shorter setate hairs dorsally. Third seg- 

 ment elongate, narrowed subbasally and gradually ex- 



