LEPTOGASTEINAE 



ROBBER FLIES OF THE WORLD 



309 



Thorax : The mesonotum is of only moderate height, 

 long, barely convex across the top, steeply arched pos- 

 teriorly, abrupt anteriorly, with a vertical front. It 

 is coarsely pubescent laterally and widely shining over 

 the middle portion. It bears abundant, fine, mostly 

 erect pile with a band of feebly differentiated acros- 

 tical pile. No dorsocentral elements are differentiated. 

 Anteriorly the medial portion of the mesonotum is a 

 little compressed laterally. There are no stout bristles 

 on the sides of the mesonotum. Above the wing are 

 2 or 3 bristly hairs intermixed with coarse pile. Scu- 

 tellum flat, with coarse, bristly pile along the margin 

 and some on the disc. Pleuron densely pollinose over 

 the upper half of the mesopleuron, the propleuron, and 

 lower pteropleuron. The wings arise unusually far 

 back on the thorax and all the legs attached quite far 

 forward. The metasternum is pilose posteriorly and 

 laterally, the postmetacoxal area is heavily chitinized, 

 with a medial seam formed by a medial extension of 

 the lateral chitin. The presternum is fused laterally. 



Legs: All of the femora tend to be a little dilated 

 or swollen distally, the middle pair more than the 

 anterior pair. The hind femur, which together with 

 its tibia are much longer, are conspicuously swollen 

 distally. This tibia is likewise greatly swollen, widest 

 in the middle and narrowed toward either end. Bris- 

 tles are absent except at the apex of the tibia. The 

 hind femur and its tibia bear a dense, conspicuous 

 fringe of rather long, erect, coarse pile on all sides, 

 but the pile of the medial surface is more or less ap- 

 pressed; at the apex ventrally are 3 stout bristles. 

 Only the first three hind tarsal segments bear bristles 

 and these are stout. On the next two segments they 

 are replaced by minute but very stout spines curled 

 against the segment. The tarsal segments of the first 

 four legs are similarly constructed. Anterior and 

 middle femora and their tibiae with similar fringes 

 of pile, less dense, shorter and therefore less conspicu- 

 ous. The claws are long, slightly curved, sharp, ap- 

 posed and the stout empodium is nearly as long as the 

 claw. 



Wings: The wings are long and rather slender, 

 tinged with smoky brown, often with lighter spots 

 and sometimes a violet reflection. The discal cell is 

 closed with one vein, the medial crossvein, the fork 

 of the fourth vein being far towards the base and the 

 rectangular anterior crossvein opposite the base of the 

 fourth posterior cell. Anal cell closed with a long 

 stalk. Alula absent, the ambient vein complete. 



Abdomen : The abdomen is elongate, longer than the 

 wing, clavate or club-shaped distally and beginning to 

 widen at the base of the third segment. The second 

 and third segments are rather elongate and cylindri- 

 cal. First segment without bristles, but only rather fine, 

 erect, bristly pile which is not very long. The sides 

 of the second segment on the basal half have a rather 

 abundant fringe or patch of erect, long, stiff hairs. 

 Remainder of the abdominal pile scanty, fine, subap- 

 pressed and setate. The sternites with similar, slightly 



longer pile. Females with eight tergites, the eighth 

 tergite about a third as long as the seventh. 



Distribution: Ethiopian: Lasiocnemus a/finis Her- 

 mann (1926) ; albipila Hermann (1926) ; anthraeinus 

 Janssens (1952) : fascipennis Engel and Cuthbertson 

 (1939) ; grisekinctipes Speiser (1913) ; hermanni Jans- 

 sens (1952); hyalipennis Janssens (1952); lugens 

 Loew (1858) ; obscuripennis Loew (1851) ; pUipes 

 Curran (1927) ; violacea Hermann (1926). 



Genus Systellogaster Hermann 



Figubes 206a, 602, 1180, 1188, 2042, 2052, 2059 



Systellogaster Hermann, Verh. zool.-bot. Ges. Wien, vol. 74-75, 

 p. 149, 1926. Type of genus : Euscelidia fascipennis Schiner, 

 1867, by original designation. 



Medium size flies with clavate, cylindroid abdomen, 

 the hind femur and tibia gently dilated distally and 

 with a moderately long brush of pile on the femur. 

 From Lasiocnemis Loew it differs by the short empo- 

 dium which, though stout, is only half as long as the 

 claws; also by the short pilose mesonotum; and the 

 gradual dilation of the hind tibia, which is compara- 

 tively slightly swollen. The epistoma is concave and 

 there is no trace of the basal segment of the palpus, or 

 rather the remains of the basal segment of the palpus is 

 completely fused. Finally, the anal cell is widely open 

 and the discal cell ends normally; the wing is often 

 fasciate. Length 12 mm. 



Head, lateral aspect: The eye is strongly convex 

 anteriorly and nearly plane for the greater middle 

 part of the posterior profile, but strongly convex 

 below, somewhat less convex dorsally. The occiput is 

 thick but chiefly developed medially; it gradually 

 slopes down to the eye margin. Pile of occiput only 

 moderately abundant, but rather long, the submarginal 

 elements stiff and bristly ; true bristles are absent. The 

 proboscis is robust and directed horizontally forward ; 

 it is slightly longer than the head but projects con- 

 siderably beyond the face. The apex is bluntly rounded 

 and the whole proboscis rather stout and cylindrical 

 without dorsal ridge; the apex bears a few, short, stiff 

 hairs and a lateral row of slightly longer, stiff hairs 

 on either side just before the middle of the proboscis. 

 Palpus clearly of one segment, the remains of the basal 

 segment completely fused, especially medially, and the 

 lateral surface membranous. The palpus is com- 

 paratively small, robust, cylindrical and obtuse, bearing 

 close to the apex 3 or 4 fine, stiff hairs on the dorsolateral 

 aspect and with an additional bristly hair arising 

 laterally near the base and 1 or 2 similar hairs arising 

 from the vestige of the basal segment. The antenna 

 is attached at the upper sixth of the head and moder- 

 ately long; the first two segments are short, the first 

 shorter than the second, the second beadlike and wider 

 than the third. The third segment is moderately 

 slender, attenuate apically, 1% times as long as the 

 combined length of the first two and bears a slender 

 style slightly longer than itself. This style is slightly 



