DASYPOGONINAB 



ROBBEK FLIES OF THE WORLD 



255 



as the combined length of the first two segments, lat- 

 erally compressed, considerably widened on the outer 

 half, attenuate basally and rather abruptly narrowed 

 apically. It has a short microsegment which carries 

 a minute, apical spine. First segment with some mod- 

 erately long, bristly hair dorsally and ventrally, sec- 

 ond segment with similar bristles and these are a little 

 more stout; third segment with 10 to 12 moderately 

 long, dorsal bristles. 



Head, anterior aspect : The cheeks are not developed 

 below the eye. The face below antenna is about two- 

 fifths the head width and slightly divergent below. 

 Subepistomal area rather large, deeply concave but 

 nearly horizontal or only slightly oblique. The face is 

 pubescent, densely, long, fine pilose, with 4 pairs of 

 long, slender bristles above the epistomal margin. 

 Front very slightly widened, pollinose, with abundant, 

 long, fine, bristly pile. Vertex but moderately ex- 

 cavated, slightly narrowed, the ocellarium large, promi- 

 nent with very large, anterior ocellus and bearing 5 or 

 6 pairs of rather slender, anteriorly curved, bristly 

 hairs and at least as many pairs of longer, stiff hairs 

 posteriorly. Anterior eye facets strongly enlarged 

 centrally. 



Thorax: The thorax is minutely appressed micro- 

 pubescent. Pile of mesonotum very dense, excep- 

 tionally fine, long and crinkled. There is a wide band 

 of acrostical pile separated by a narrow apilose area. 

 Dorsocentral pile undifferentiated, except posteriorly; 

 while not or scarcely longer, it is very slightly stiffer 

 in character. Humerus with fine pile only. Laterally 

 the bristles consist of 2 long, moderately stout noto- 

 pleural, no supraalar, and on the postalar 2 or 3 long, 

 stiff hairs. Whole scutellum including the margin 

 with quite long, fine pile. Scutellum slightly convex, 

 moderately thick, pollinose. Propleuron with scanty, 

 fine pile ventrally and with a band of similar pile on 

 the pronotum and on the posterolateral segment. Bris- 

 tles absent. Mesopleuron densely, long, fine pilose on 

 the posterior half; similar pile long and abundant on 

 the posterior half of the sternopleuron, the anterior 

 and posterior hypopleuron and pteropleuron, and 

 widely over the metapleuron. Bristles are absent. 

 Lateral metanotum micropubescent only ; lateral meta- 

 sternum with abundant, long pile which becomes espe- 

 cially dense, long and prominent on the elongate, 

 shining, heavily chitinized ventral metasternum. 

 Postmetacoxal area membranous; anterior basalare 

 with numerous, long, fine hairs ; the tegula with setae. 

 Presternum small and dissociated. 



Legs: All of the femora are slender, the hind pair 

 elongate, very slightly dilated toward the apex and all 

 of the femora with long, abundant, subappressed, stiff 

 setae, dorsally and laterally. These setae become longer 

 medially and on the first two pairs of legs they are 

 longer posteriorly. The following complement of 

 short, weak bristles is present: on the hind femur 6 

 lateral including 1 at the apex, 1 medial at the apex, 

 and 1 dorsolateral and 1 dorsomedial bristle at the sub- 

 apex. There are 7 or 8 weak ventrolateral bristles and 



535914— 62— pt. 1 18 



numerous long, suberect setae ventrally on the hind 

 femur. Hind tibia slender throughout, the bristles 

 stronger, the apex at most very slightly widened. This 

 tibia is as long as the femur and has 4 to 5 dorsomedial, 

 2 medioventral, 3 dorsolateral, 3 stout ventrolateral, 

 and 2 additional, quite fine, ventrolateral bristles on 

 the basal half. Middle femur with 4 anterior bristles, 

 including 1 at the apex and 1 at the subapex antero- 

 dorsally and posterodorsally. Middle tibia with 3 pos- 

 terodorsal bristles, 1 of them at the extreme base and 

 the last at the middle, and 4 anterodorsal, 1 also at the 

 base and the last at the outer fourth. There are 2 

 quite strong, ventral bristles on the outer half and 5 

 posteroventral shorter but also stout bristles. At the 

 apex are 2 dorsal, 1 anterior, 1 posterior, and 4 ventral 

 bristles. Anterior femur shorter than the middle pair 

 and with 2 weak bristles anteriorly near the apex ; this 

 tibia has 3 dorsal, 5 or 6 posterior and a pair of quite 

 stout, rather long, ventral bristles subapically. The 

 apex of this tibia has a strongly produced, anteroventral 

 lobe carrying a curved spine. Anterior basitarsus un- 

 modified; comparatively slender, as long as the next 

 two segments combined ; all tarsi end in slender, sharp 

 claws, well developed spatulate pulvilli, and a long, 

 bristle-like empodium swollen at the base. 



Wings: The marginal cell is widely open; anterior 

 branch of the third vein ends at the wing apex; pos- 

 terior branch ends a considerable distance behind the 

 wing apex ; first posterior cell widely open, but by less 

 than its maximum width; fourth posterior cell open 

 but strongly narrowed; the anterior crossvein enters 

 the discal cell at the basal third ; the middle end vein 

 of the second basal cell is short ; the anal cell is closed 

 in the margin ; the alula is moderately wide, the ambient 

 vein complete. 



Abdomen: The abdomen is subclavate, distinctly 

 more narrow basally than the mesonotum; convex 

 across the tergites, and the second and third tergites 

 especially arched and convex from the lateral aspect; 

 the second has an additional, subbasal arch and this 

 tergite is distinctly longer than the remaining. In the 

 male seven tergites present, the sixth two-thirds as 

 long as the fifth, the seventh is less than half as lone; as 

 the sixth. Pile of the abdomen minute but abundant 

 and subappressed dorsally, becoming slightly longer 

 laterally but quite long and fine on the sides of the first 

 and second tergites. Bristles absent on all tergites. 

 First tergite apilose, second and third with clumps of 

 long, fine pile similar to the pile of the metasternum. 

 Male terminalia half-rotate and generally similar to 

 Neolaparus. The ventrally placed epandrium is promi- 

 nent, elongate, arched and scooplike; it is fused to the 

 thin, equally long and prominent proctiger which is 

 truncate and hemicylindrical apically. The hypan- 

 drium is obtuse, ventrally rounded and extends up 

 laterally to meet the epandrium. Midway it encloses 

 tightly the basally broad gonopod but is not fused to it. 

 Gonopod with rectangularly bent, stout process which, 

 after the bend, is posteriorly produced. Cavity open 



