DASYPOGONINAB 



ROBBER FLIES OF THE WORLD 



253 



rather widely spaced ; the upper occipital pile is some- 

 what more stiffened. The proboscis is moderately 

 long, laterally compressed, smooth and polished with 

 high dorsomedial ridge. The apex is slightly attenu- 

 ate from the dorsal aspect and bears a few, fine hairs. 

 The base is not swollen and has 5 or 6 long hairs below 

 and it is directed nearly horizontally forward. The 

 palpus sometimes appears to have one segment only; 

 there is a very short basal segment, more in evidence 

 in those individuals in which it is sometimes elbow- 

 shaped. It is about 4 times as long as wide, cylindrical, 

 not porate and bears a number of long, stiff hairs 

 ventrally and at the apex. The antenna is attached 

 just above the middle of the head in profile, of mod- 

 erate length; the first segment is a little shorter than 

 the second. The third segment is twice as long as the 

 second; it is greatly expanded dorsoventrally just be- 

 fore the. middle and again narrowed near the apex. It 

 bears a rather short, conical, apically truncate sub- 

 segment to which is attached a small, conical spine. 

 First segment with only 2 or 3 setae below and 3 above ; 

 second segment with 4 long setae ventrolateral^ and 

 6 above. Both segments largely pubescent. Third 

 segment with several rather long, appressed setae in 

 the middle dorsally. 



Head, anterior aspect: The head is nearly twice as 

 wide as high. The face below antenna is approxi- 

 mately one-third the head width and slightly divergent 

 below. The subepistomal area is relatively small, al- 

 most horizontal, concave and bare. Face micropubes- 

 cent, with thinly scattered, fine pile over the whole, 

 except immediately beneath the antenna and with 2 

 pairs of rather strong and 2 or 3 pairs of quite weak 

 bristles along the epistomal margin; in the middle 

 immediately above the epistoma there is often an addi- 

 tional pair of still more stout bristles. The front is 

 of the same width as the face, the vertex slightly con- 

 vergent; the front bears laterally along the eye 

 margin a group of about 7 fine hairs and 4 or 5 

 others submedially. Vertex moderately excavated with 

 rounded sloping sides. Ocellar protuberance moder- 

 ately high with large frontal ocellus; the sides are 

 sloping and there are 5 pairs of short, fine hairs behind. 

 Eye facets enlarged centrally. 



Thorax : The thorax, including the pleuron, is polli- 

 nose. Mesonotum with pile restricted to acrostical 

 and dorsocentral rows of stiff, small, sharp setae and 1 

 or 2 rows of fine hairs laterally and 4 or 5 fine hairs 

 on the humerus. The complement of stout, moderately 

 long, lateral bristles consists of 1 notopleural, 1 supra- 

 alar, 1 postalar, and no scutellar bristles. All pre- 

 sutural setae minute. Scutellum thick, pollinose with 

 about 7 minute setae on each side. Lower propleuron 

 with 10 or 12 fine hairs; pronotum with 20 or more 

 fine hairs, 5 on the posterior section; 3 or 4 on the 

 anterior prolongation of the mesopleuron, 4 or 5 very 

 short hairs posteriorly on the mesopleuron, similar 

 groups on the upper sternopleuron, anterior hypopleu- 

 ron, and pteropleuron. Metapleuron with a vertical 

 row of 9 delicate hairs. Metanotal slopes micropub- 



escent only ; metasternal slopes with 10 or 12 fine hairs ; 

 ventral metasternum with 5 or 6 fine, short hairs; post- 

 metacoxal area membranous; tegula pubescent only. 

 Presternum quite small and dissociated. 



Legs : The legs are elongate and rather slender, the 

 hind femora slightly dilated apically. All the legs are 

 densely covered with appressed, basally thickened, 

 attenuate setae including the ventral surfaces of the 

 femora, and their tibiae. Tibial setate brushes present 

 only on apical sixth of hind tibia and narrowly along 

 whole anterior tibia. The hind femur has 2 medial 

 bristles at the apex, 1 lateral and 1 dorsal subapical, 

 besides 6 lateral bristles distributed over the middle of 

 this surface, and 4 ventral bristles on the basal half. 

 The hind tibia bear somewhat longer bristles, 4 dorsal, 



3 anterior, 4 ventral, and 4 ventromedial bristles. 

 Hind tibial apex with 8 long bristles. The middle 

 femur bears 3 anterior and 2 posterior on the basal 

 half, has 1 anterior and 1 posterior at the apex, and 2 

 basal ventral elements. The middle tibia bears 4 dorsal, 



4 anterior, 5 posterior and 2 quite long, stout ventral 

 bristles beyond the middle; the apical circlet has 10 

 bristles. Anterior femur with only 1 bristle at apex 

 anteriorly and posteriorly and 2 basal ventral elements; 

 its tibia has 3 dorsal, 3 anterodorsal, 5 posterior, and at 

 the apical fifth a pair of long, oblique, stout, ventral 

 bristles. Apex with a single exceptionally long ante- 

 rior, 2 short anterior, 2 dorsal, 1 posterior and also an 

 unusually long, stout curved spine pressed inward 

 against a nodular, flangelike expansion of the basitarsus. 

 All tarsi end in well developed pulvilli; empodium 

 three- fourths as long as the sharp claws. 



Wings : The wings are of moderate width and some- 

 times broad; they are hyaline or lightly or deeply 

 tinged with brown. Marginal cell widely open, ante- 

 rior branch of third vein ends at the apex ; all posterior 

 cells may be widely open or the fourth posterior cell 

 may be narrowed at the margin. Anal cell open, second 

 basal cell ends in two veins; alula large, ambient vein 

 complete. 



Abdomen : The abdomen is long and rather slender, 

 subcylindrical, slightly clavate posteriorly and as long 

 as the wings. The first tergite is slightly swollen and 

 convex laterally. The pile of the abdomen, including 

 the lateral margins, consists of dense, basally stout, 

 sharp, subappressed microsetae. There is a large, 

 apilose, pollinose, raised triangular area at the base of 

 the second tergite. Bristles present on the sides of the 

 first 3 tergites; there usually are 3 on the first tergite, 

 2 on the second and 1 on the third tergite. Second 

 sternite with fine pile, others with stout setae. The 

 male with seven tergites; the female with eight, the 

 eighth long. The male terminalia is conspicuous and 

 large, and clublike and completely rotate. It is domi- 

 nated by the remarkably deep, bowllike swelling of the 

 inverted epandrium, uncleft and with transverse pos- 

 terior margin, to which is fused the even longer, equally 

 deep and swollen, thinned, hemicylindrical proctiger 

 (I interpret the whole of this structure as belonging 

 to the ninth and tenth segments but it is possible it 



