DASYPOGONINAB 



ROBBER FLIES OF THE WORLD 



191 



Distribution: Palaearctic: Sisyrnodytes brevis Mac- 

 quart (1838) [ = contrarius Walker (187 1) , -floe >c %ls Loew 

 (1856), nilicola Kondani (1850)] ; leucopliaetus Seguy 

 (1930) ; rufus Seguy (1931). 



Ethiopian: Sisyrnodytes aterrimus Engel (1929); 

 curtus Wiedemann (1819); dlsjunctus Seguy (1931); 

 major Adams (1905) ; niger Bezzi (1906) ; niveipilosw 

 Kicardo (1925). 



This is a small but characteristic Ethiopian genus 

 which extends into the Palaearctic region only along 

 the northern African coast. 



Genus AcnepJialum Macquart 



Figubes 140, 524, 1032, 1044, 1739, 1757, 1759 



Acnephalum Macquart, Dipteres exotiques, vol. 1, pt. 2, p. 51, 

 1838. Type of genus: Acnephalum, olivieri Macquart, 1S3S. 

 Designated by Engel, 1929. 



Broad, exceptionally robust and medium size flies; 

 the short, rather flattened abdomen is wider than the 

 thorax and sometimes bears wide, lateral fringes of 

 dense pile. Bristly hairs are present laterally on the 

 tergites. Readily recognized by the absence of pul- 

 villi and the rather long spur directed basally from 

 near the base of the second submarginal cell. Dis- 

 tinguished from the closely related Sisyrnodytes Loew 

 by the open second posterior cell and the ambient vein 

 which ends at the anal cell but is wholly absent in 

 Sisyrnodytes. Length 10 to 13 mm. 



Head, lateral aspect : The head is of moderate length, 

 strongly convex both anteriorly and posteriorly. The 

 face is short, but convex and retreating, the subepistoma 

 broad and concave. The eye is somewhat narrowed 

 above and distinctly longer below. The occiput is 

 especially prominent above the middle. Pile of the 

 occiput is dense and abundant, short near the eye 

 margin, longer medially with some moderately stout, 

 sharp bristles mixed in with the pile on the dorsal third. 

 The proboscis is short, more or less laterally compressed 

 with a thin, high, medial ridge. The immediate apex is 

 narrowed, rounded and pointed bluntly. It is longer 

 than the face and is directed obliquely downward. 

 Palpus large, with two cylindrical segments. The first 

 segment is small, free and excavated. The second seg- 

 ment is tapering and bluntly pointed at the apex with 

 numerous, long, bristly hairs but no pore. The antenna 

 is attached at the upper third of the head ; the first two 

 segments are quite short, the first with 2 or 3 slender 

 bristles or bristly hairs below which are almost as long 

 as the second segment. Second segment with a 

 similarly long bristle both above and below. The third 

 segment is exceptionally long and slender, slightly 

 swollen at the base, with a minute, basal microsegment 

 and a considerably longer, slender microsegment bent 

 downward. 



Head, anterior aspect: Below the antenna the face is 

 about one-fourth the head width and divergent below. 

 The face has dense, opaque, fine, matted, appressed pile 

 which is directed downward. There are a few long, 



535914— 62— pt. 1 14 



stiff, bristly hairs along the lower, lateral eye margins. 

 Front with only short appressed pile and some sparse 

 pubescence. The width at vertex is nearly the same as 

 the upper face. The ocellar protuberance is extremely 

 large, has 3 or 4 pairs of slender bristles, long and 

 partly divergent. Some species have only a tuft of fine, 

 delicate pile. The upper medial central eye facets are 

 rather strongly enlarged. 



Thorax : The mesonotum densely covered everywhere 

 with moderately long, subappressed, stiff, setate pile. 

 There is also some curly pile situated in several patches 

 anteromedially, an elongate patch on the inner side of 

 each humerus and a short patch in the anterior middle 

 of the mesonotum on either side of the middle vitta or 

 band. Bristles as follows: notopleural 5, supraalar 2 

 or 3, postalar 7 or 8, all light brownish yellow and 

 appressed. Scutellar margin with 6 or 7 pairs of 

 slender bristles. The prescutellar area bears slightly 

 longer pile, the metanotal slopes are not pilose. 

 Pleuron for the most part shining bare, mesopleuron 

 in part micropubescent and with considerable, rather 

 long, matted pile. Propleuron with long pile ; the pro- 

 notal collar has numerous, quite long, slender, brownish 

 yellow bristles and laterally some brownish yellow pile. 

 Metapleuron strongly convex and protuberant, with a 

 wide, central, oval patch of long, slender, brownish yel- 

 low bristles and some slender, undulate or crinkled pile ; 

 some of the propleural or mesopleural pile is wavy. 

 Metasternum laterally with pile. Postmetacoxal area 

 membranous. Tegula with a matted patch of setae. 



Legs: Hind femur stout, with rather long laterally 

 fine, dorsally stiff, brownish yellow pile which is sub- 

 appressed. Apex with a stout, sharp, somewhat curved 

 bristle dorsolaterally and opposite it dorsomedially a 

 row of 3 transverse bristles. Ventrolateral and ventro- 

 medial margins with an abundant fringe of quite long, 

 slender, bristly hairs. Tibia with long, appressed, 

 opaque pile and stout bristles which consist of a double 

 row of long, stout elements, 4 dorsomedial, 6 dorsolat- 

 eral, and at the apex 1 weak dorsolateral and 1 ex- 

 tremely stout, spinous bristles, as well as 1 dorsomedial, 

 3 medial, 5 ventral, and 1 ventrolateral bristles. Middle 

 femur with a cluster of 3 dorsomedial subapical bristles 

 and 4 dorsolateral near the apex. Middle tibia with a 

 double dorsal row, more strongly oblique than those of 

 the hind tibia, containing 6 posterior, 4 anterior, and a 

 posterior row of 5 or 6 slender bristles, besides a postero- 

 ventral row of 5 bristles. Anterior femur with 2 bristles 

 posterodorsally near apex. Anterior tibia with long, 

 strongly appressed or oblique bristles, a double row 

 dorsally of 4 or 5 bristles partly tripled on the outer 

 half and with more slender, longer elements posteriorly, 

 consisting of 6 or 7 bristles. Apex with 6 bristles and 

 without spine. Claws long, curved at the base gently 

 instead of at apex, stout at the apex but bluntly pointed. 

 Pulvilli absent. Empodium about half as long as 

 claws, bladelike and flattened. 



Wings: The wings are broad, with the veins some- 

 times margined with brown, or nearly hyaline. Mar- 

 ginal cell open. The anterior branch of the third vein 



