338 



UNITED STATES NATIONAL MUSEUM BULLETIN 224 



toma, a patch of shorter, bristly pile. Subepistoma long 

 and oblique. Front short, with a tranverse band of pu- 

 bescence, a sublateral groove continued on to the vertex 

 and along the eye margins a patch of slender bristles 

 and bristly hairs. The front is deeply excavated, with 

 steep sides; the ocellarium is small, with a few short 

 hairs behind the ocelli and a single pair of long bristles 

 between the ocelli. Sides of the vertex opposite the 

 ocelli with a dense patch of coarse pile. Postvertex 

 widened and flared only to a moderate extent. 



Thorax : The mesonotum is comparatively low and 

 densely covered with minute, flat appressed, curled 

 setae. Humerus with many long, stiff, erect, bristly 

 hairs anteriorly and appressed setae behind. The 

 lateral mesonotal bristles are few, rather weak and not 

 very long. The complement contains 1 notopleural, 1 

 supraalar, 1 or 2 very short postalar and along the 

 scutellar margin 2 or 3 pairs of still shorter bristles 

 little more than setae. Scutellum large, gently convex 

 densely appressed setate like the mesonotum. Posteri- 

 orly in the dorsocentral row there are a few, fine more 

 or less erect short hairs. Pronotum with 7 or 8 pairs 

 of stout bristles and other pile. Remainder of pro- 

 thorax with stiff, bristly hairs more abundant on the 

 cervical sclerite. More than the posterior half and the 

 dorsal portion of the mesopleuron with erect, long, 

 bristly hairs. The posterior corner of the mesopleuron 

 with 1 long, stout bristle. A few fine hairs on the 

 pteropleuron, the metapleuron with a broad band of 

 about 25 bristles, all rather stout. Metanotal callosity 

 pollinose only. Postmetacoxal area membranous but 

 narrowed by the medial extension of the lateral chitin. 

 Prosternum widely fused laterally. 



Legs: All the femora are swollen, the hind femur 

 especially, but its lower surface is plane, upper surface 

 arched and convex. Pile of legs abundant, appressed 

 and setate with some long fringes of fine pile beneath 

 the anterior femur, shorter beneath the hind femur and 

 more scantily beneath the anterior and posterior tibiae. 

 The hind tibia is stout throughout its length. The hind 

 femur bears 5 short spines set in tubercles along the 

 posteroventral margin. This tibia has a single, short, 

 anterodorsal bristle near the middle and the apex 

 carries 5 or 6 weak bristles. Middle femur with a stout 

 bristle anteriorly at the outer third, a short one antero- 

 dorsally at the same level. This tibia has 4 short, weak 

 bristles dorsally, 6 bristles anteriorly, 4 of which are 

 long, conspicuous and stout and 3 weaker posteroven- 

 tral bristles, besides a very stout, distal, ventral bristle. 

 Anterior femur with abundant, long, coarse pile ven- 

 trally, its tibia with 2 or 3 prominent, long, ventral 

 bristles and a few, fine, short, bristly hairs posteriorly. 

 Claws comparatively slender, sharp, bent at apex ; the 

 pulvilli and bladelike empodium well developed. 



Wings : The marginal cell is closed, with a long stalk ; 

 the anterior branch of the third vein ends at or slightly 

 above the wing apex, the posterior branch far behind, 

 the base of the second submarginal cell rises rather 

 abruptly from the plane, third vein. First posterior 

 cell widely open, fourth posterior cell closed with a 



moderately long stalk. Anal cell closed, anterior cross 

 vein rectangular, entering the discal cell at the basal 

 third. Alula large and the ambient vein complete. 



Abdomen: The abdomen is robust and relatively 

 short, shorter than the wings. At the base it is as wide 

 as the mesonotum, only slightly narrowed posteriorly, 

 its sides therefore not quite parallel and the pile is 

 minute, dense, appressed and setate. Sides of first ter- 

 gite with 3 short, but quite stout bristles, second to fifth 

 tergites laterally in the middle of each side, each with 1 

 short but conspicuous, stout bristle. Males with six ter- 

 gites, females with six visible tergites, the seventh com- 

 pletely tucked beneath the sixth. Male terminalia 

 large, completely rotate, the epandrial element forming 

 a great, swollen, anteriorly bulbous or boatlike struc- 

 ture. The gonopod almost but not quite closes off the 

 true ventral aspect of the cavity. Female terminalia 

 rather long, narrow and laterally compressed. 



Distribution: Ethiopian: Storthyngomerus aurea 

 Bromley (1935) ; Byrnes Walker (1855) ; testaceus Mac- 

 quart (1838) ; tridentatus Fabricius (1805). 



Genus Rhopalogaster Macquart 



Figures 250, 284, 619, 625, 1221, 1222, 1230, 1231, 1298, 1307, 2095, 

 2098, 2143 



Rhopalogaster Macquart, Histoire naturelle des insectes, di- 

 pteres, vol. 1, p. 279, 1834. Type of genus : Laphria longi- 

 cornis Wiedemann, 1828, by monotypy. 



Flies with short pile, greatly reduced bristles. The 

 head is short and wide and the face is short, rounded 

 and retreating below. They may be readily recognized 

 by the strongly petiolate or constricted abdomen and 

 the very long antenna. The first segment is usually 10 

 times as long as the second; the third segment varies 

 from iy 2 to more than 2 times the combined length of 

 the first two segments. The wings are slender and the 

 first posterior cell is closed. Length 15 to 20 mm. 



Head, lateral aspect: The face is short, not quite 

 plane and at the most only very slightly concave. Eye 

 of moderate length, equally developed above and below ; 

 it is rather strongly convex anteriorly, gently convex 

 behind. The occiput is exceptionally thick and well de- 

 veloped especially towards the medial portion; it con- 

 tinues to be thick above and below and slopes rather 

 rapidly down to the eye margin. In dorsal and ventral 

 aspects the eye is strongly recessive at the posterior 

 corners. Pile of occiput dense, long and fine, with only 

 very slender, dorsal bristles scarcely more than stiffened 

 hairs in the type of genus. Proboscis, long, extending 

 well beyond the face and compressed laterally ; the apex 

 is bluntly pointed and tapered both from above and 

 below. The immediate base of the proboscis is dis- 

 tinctly swollen but only ventrally. The medial ridge is 

 absent; the apex bears some fine, short pile above and 

 below, the base ventrally has a number of long, fine 

 hairs. Palpus clearly of two segments but the first seg- 

 ment is small, short and excavated ; the second segment 

 is also small and is cylindrical, with apical bristles. 



