ROBBER FLIES OF THE WORLD 



539 



with 10 to 12 bristles varying from stout to slender. 

 Metanotal slopes with a large patch of long, fine pile. 

 Lateral and ventral metasternum with numerous, fine 

 hairs; postmetacoxal area membranous; posterior bas- 

 alare with 4 setae; squama with a multiple fringe. 

 Prosternum connected to lateral propleuron by a nar- 

 row strip of chitin. 



Legs: All the femora are stout; the anterior and 

 middle femora are distinctly thickened toward the base, 

 the hind femur slightly elongate. The hind femur is 

 nearly li^ times as long as the middle femur. Pile of 

 these femora abundant, appressed, stiff setate. Bristles 

 are very numerous and for the most part rather long 

 and exceptionally stout. On the ventral surfaces of the 

 fii-st 4 legs they are curved, very sharp, tuberculate and 

 spinelike. The hind femur bears 1 dorsomedial bristle 

 at apex, a double bristle dorsomedially and subapically, 

 and 2 others in the same row on the outer fourth. The 

 dorsolateral row contains 7 especially long bristles, the 

 ventrolateral row 11, the ventral row 10, which are also 

 long; the hind tibia bears 6 long dorsal, 3 similar, 

 lateral bristles wliicli are quite appressed and 4 ventral, 

 also 4 or 5 fine, medial and 2 stout medial bristles near 

 the base and apex ; brush of setae restricted to the tibiae 

 and the first segment of the tarsi; apical circlet with 

 8 bristles. Middle femur with an oblique row of 4 

 posteroapical, 6 posterior, 10 anterior, 12 postero- 

 ventral, and 8 anteroventral ; all these bristles are 

 spinelike and black. The middle tibia has 4 dorsal, 4 

 posterior and fine, bristly hairs beneath. 



Anterior femur with an oblique row of 3 anteroapical 

 and a double row of stout, long, curved, sharp, ventral, 

 spinous bristles, increased to 4 rows on the basal half, 

 a total of 30 bristles. Anterior tibia with 5 short, dorsal 

 bristles, 2 weak posterior at the apex, 1 posterior, 1 

 posteroventral bristle, and an anteroventral fringe of 

 long, slender, bristly hairs. First segment of the 

 basitarsus slightly longer than the second, each with 2 

 stout, apical dorsal bristles, 2 longer anteroapical, 1 

 long, apical posteroventral, 1 still longer, posterodorsal 

 bristle. Tarsus ends in large pulvilli, a stout empodium 

 two-thirds as long as claw, and in a stout, moderately 

 sharp claw curved from the base. 



Wings : The marginal cell is closed with a short stalk ; 

 the anterior branch of the third vein ends distinctly 

 above wing apex, the posterior branch ends beliind. 

 The second submarginal cell begins at the end of the 

 discal cell. First posterior cell slightly narrowed in the 

 middle ; discal cell narrowed in the middle ; lower end 

 vein of discal cell strongly drawn towards the base. 

 The fourth posterior cell is closed with a long stalk; 

 anal cell closed ; second basal cell ends in 2 veins ; alula 

 large ; ambient vein complete. 



Abdomen : The abdomen is subcylindrical or some- 

 times with the sides flared out and only slightly rolled. 

 Abdomen distinctly tapered ; the first tergite is swollen 

 laterally and ridged. Pile of abdomen scanty, short, 

 flat appressed and setate with some slightly longer, erect 

 pile on the lateral margin. A few fine, long, erect hairs 

 present on the stemites. First tergite with 3 lateral 



bristles and a cluster of 5 or 6 bristles in the middle 

 laterally on the second to fifth tergites, and with fewer 

 elements on the sixth and seventh tergites. Sternites 

 characteristically with similar, lateral, central clusters 

 of bristles. Abdomen as long as the wings. In the 

 males eight tergites present, the eighth only a fifth as 

 long as the seventh and of uniform width; seven ter- 

 gites present in the female, the eighth incorporated in 

 the ovipositor. Male terminalia with the superior for- 

 ceps robust, divergent but meeting medially at apex; 

 apical part sometimes notched and a wide space is left 

 from dorsal aspect. Proctiger flat and extended ob- 

 liquely upward. Gonopod short, the hypandrium still 

 shorter. Whole cavity widely open from the ventral 

 aspect. Eighth sternite quite short, receding from its 

 posterior margin in the middle. Female terminalia 

 with the ventral portion strongly compressed laterally 

 but with the upper portion forming a basally broad, 

 slightly convex hood, which rests above the lower por- 

 tion ; apex attenuate. 



Distribution : Palaearctic : Echthistus cognatus Loew 

 (1849) [=ruflventris Meigen (1820)]; rufinervis 

 Meigen (1820) [=femoralis Megerle Ms., in Meigen 

 (1820), ffiavescens Macquart (1834)]. 



Genus Hoplopheromerus Becker 



FiGtTBES 342, 757, 1525, 1534, 1573, 2191, 2295, 2353 



Hoplopheromerus Becker, Ent. Mitt., vol. 14, p. 241, 1925. Type 

 of genus : Asilus armatipes Macquart, 1855, by present des- 

 ignation. This is the second of two species. 



Moderately large flies distinguished in both sexes by 

 the very dense brush of almost spinous bristles along 

 the middle of the anterior margin of the thickened, 

 middle femur, together with an exaggerated row of 

 stout bristles anteroventrally on the corresponding 

 tibia. The face is rather short, the very low ventral 

 gibbosity gently rises in the middle, accentuated only 

 by the recession of the eye ; the upper part of the face 

 is plane with the eye. Pile of the thorax minute, es- 

 pecially in the female, and the abdominal pile also 

 shorter in the female. Length 24 to 30 mm. 



Head, lateral aspect: The face is nearly or quite 

 plane with the eye on the upper half, with a low, 

 rounded, gently rising gibbosity on the ventral half, 

 perhaps slightly more prominent in the male ; the eye is 

 strongly convex anteriorly, convexly recessive at the 

 extreme, lower corners. Occiput moderately thick 

 throughout ; pile of occiput moderately abundant and 

 fine, with slender bristles beginning shortly below the 

 middle of the head; the dorsal elements are distinctly 

 proclinate, though very little stouter than the lower 

 elements ; there are perhaps 20 on each side. The pro- 

 boscis is slender, attenuate from the base, more strongly 

 attenuate from the dorsal aspect; the base is laterally 

 widened; apex rather pointed, with some stiff, bristly 

 hairs along the dorsal margin on the outer fifth and 

 others apically and ventrally Just beyond the middle. 

 There are 2 pairs of rather long, oblique, bristly hairs 



