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UNITED STATES NATIONAL MUSEUM BULLETIN 2 24 



Genus Borapisma Hull 



FlGUEE 621 



Borapisma Hull, Ann. Mag. Nat. Hist., ser. 12, vol. 10, p. 887, 

 1957. Type of genus : Borapisma chinai Hull, 1957, by 

 original designation. 



Medium size flies with robust but clavate abdomen; 

 characterized by the strongly swollen hind femur of the 

 male, which is plane below and also by the very long, 

 prominent, third antennal segment, which is like that 

 found in Rhopalogaster Macquart. They differ in the 

 open, first posterior cell, the distally swollen femur and 

 the strong concavity just below the middle of the face. 

 The proboscis is quite truncate at apex, and the lower 

 face protuberant with long, slender bristles. Supraalar 

 sclerite of mesonotum with a posteriorly directed pro- 

 tuberance. Length 17 mm. including the antenna. 



Head, lateral aspect : The face protuberant above and 

 merged with the protuberant front. Across the middle 

 of the face is a marked, transverse depression or con- 

 cavity nearly plane with the eye and the lower third of 

 the face is rounded and gibbose and, comparable to the 

 upper face, extensive. Occiput prominent everywhere 

 except at the immediate vertex ; it bears quite abundant, 

 long, fine pile and bristles are restricted to the upper 

 fourth and are long and slender. Proboscis strongly 

 compressed laterally, quite truncate and punctate at the 

 apex, which bears some fine pile. From lateral aspect 

 the proboscis is a little widened or deepened towards the 

 end. Palpus slender, cylindrical, elongate, with blunt, 

 spikelike bristles. The antenna is situated on the same 

 level as the vertex, therefore at the top of the head, al- 

 though the eyes rise a little above the antennal base. 

 The first segment is elongate, at least five times as long 

 as the minute, beadlike second segment. The third seg- 

 ment is nearly twice the combined length of the first two, 

 strongly compressed laterally, a little narrowed at the 

 base and beyond the base its width is distinctly greater 

 than the width of the basal segments; the apex has a 

 minute, dorsal spine. First segment with 1 long, ventral 

 bristle and some shorter, bristly hairs below. 



Head, anterior aspect : The upper face is a little less 

 than a fourth the head width and distinctly wider below 

 and largely bare in the middle ; it bears pale, slightly 

 flattened, shining hair laterally, a few long, slender, 

 bristly hairs, and some erect pile below the antenna, 

 and on the lower basal gibbosity, on each side, is a 

 vertical row of 8 quite long, slender bristles with addi- 

 tional, smaller elements extending along the sides of the 

 subepistoma. In the middle of the lower face is some 

 long, yellow pile. Front extremely short with a deep, 

 lateral crease on the outer fourth extending back behind 

 the ocelli. Ocellar protuberance quite small with mi- 

 nute ocelli and a pair of long, slender bristles. On each 

 side the eyes rise considerably above the vertex. 



Thorax : The thorax is wide and comparatively flat- 

 tened. It is convex along the anterior margin, less so 

 behind and bears numerous, fine, curled, pale hairs, un- 

 differentiated in the middle. Along each dorsocentral 



row are about 12 long, extremely fine hairs beginning 

 anteriorly. Humerus with slender, bristly hairs and 

 bristles. Notopleuron with 1 weak, short bristle. On 

 the supraalar region above the wing is a curious pro- 

 tuberance which bears 3 backwardly directed tubercles 

 carrying stout, black, curved bristles. Postalar cal- 

 losity with 2 pale bristles. Scutellum slightly convex, 

 with the rim emarginate; the disc bears curled pile 

 similar to the pile of the mesonotum ; the margin bears 

 3 pairs of quite long, slender hairs. Metanotal callosity 

 pollinose only. Pleuron partly bare with some pollen 

 or micropubescence ; pronotum with weak bristles and 

 shorter bristly hairs. The propleuron with coarse, 

 bristly pile. Posterior half of mesopleuron with sim- 

 ilar pile, the whole dorsal border with longer, very 

 slender bristles and in the middle of the posterior bor- 

 der there are 3 stout, long, backwardly turned bristles. 

 Metapleuron with a vertical band of basally stout, dis- 

 tally fine, curved, long bristles. Postmetacoxal area 

 membranous; prosternum imited with the lateral pro- 

 pleuron. 



Legs: There is a marked sexual difference in the legs. 

 The femora are much more swollen on all pairs in the 

 males; on the first four legs the swelling is chiefly ex- 

 pressed along the middle of the femur, on the hind pair 

 most of the swelling is beyond the middle; all ventral 

 surfaces of the femora are nearly plane. The legs are 

 polished and shining, with scattered, fine, somewhat 

 appressed hairs which become rather long and quite 

 conspicuous ventrally on the first 4 femora, but less 

 abundant on the hind pair. The hind tibia is rather 

 stout, slightly arcuate, the basitarsus short, robust and 

 a little longer than the next 2 segments. Bristles are 

 reduced in number, are mostly tuberculate and rather 

 stout. The tuberculate bristles are as follows: Hind 

 femur with 1 ventrolateral on the outer third, 1 dorso- 

 lateral on the outer fourth ; and hind tibia with 4 dor- 

 solateral bristles but only long pile ventrally. Middle 

 femur with 1 posterodorsal bristle on the outer fifth and 

 1 anterodorsal bristle on the outer fourth and with a 

 conspicuous, anterior bristle near the base and 3 others 

 anteroventrally along the middle. The middle and in- 

 terior tibiae are rather short and dorsally bear quite 

 slender bristles and some fine, long, bristly hairs postero- 

 ventrally and also anteroventrally. Anterior femur 

 with about 15 long, slender, bristly hairs anteriorly on 

 the distal half and numerous, similar hairs posteroven- 

 trally. Anterior basitarsus quite short. Claws are 

 sharp ; pulvilli well developed and wide ; the empodium 

 bladelike. 



Wings : The wings are tinged with brown and with 

 a conspicuous, diffuse, dark brown spot on the apical 

 fourth before the apex, centered over the fork of the 

 third vein. Marginal cell closed with a long stalk, 

 anterior branch of the third vein nearly but not quite 

 straight, the second submarginal cell is rather wide at 

 the base but expanded only anteriorly. First posterior 

 cell open but narrowed ; posterior crossvein well devel- 

 oped. Anal cell closed with a short stalk; alula well 

 developed ; ambient vein complete. 



