576 



•UNITED STATES NATIONAL MUSEUM BULLETIN 224 



front laterally bears more than 20 quite long, slender, 

 black hairs. Vertex only moderately excavated with 

 slanting sides. Ocellar protuberance moderate with 

 vertical sides and bearing 8 pairs of long, slender 

 divergent hairs. Eye facets moderately enlarged 

 centrally. 



Thorax : The thorax is pollinose including the pleu- 

 ron; the mesonotal pile is long, fine, nearly erect and 

 microtuberculate ; some of these stiff hairs are longer 

 and stouter than others. The acrostical elements are 

 especially prominent and include a double, multiple 

 row of stiff hairs and some moderately stout bristles 

 anteriorly. The dorsocentral elements begin to form 

 long, stout bristles somewhat anterior to the notopleu- 

 ron and continue as a triple row irregularly until 

 close to the scutellum, in which area they are especially 

 long and stout. Humerus pilose only. Stout, long, 

 pale, lateral bristles are present and consist of 3 noto- 

 pleural, 4 postsupraalar, 1 suprapostalar, 4 postalar, 

 and 1 pair of widely separated scutellar bristles. The 

 postalar bristles are extremely long and their length 

 fully equals the height of the mesonotum. Scutellum 

 thick, convex, pubescent with deeply impressed, sub- 

 apical crease; the lateral third on each side bears a 

 dense tuft of long, delicate, fine, erect, pale pile. Pro- 

 pleuron with moderately abundant, long, fine pile on all 

 parts; pronotum also with 4 or 5 pairs of stout, pale 

 bristles. Upper anterior and posterior mesopleuron, 

 upper sternopleuron, the pteropleuron, the posterior hy- 

 popleuron each with 8 to 12 long, fine hairs. The hypo- 

 pleuron lacks a differentiated patch of pubescence. 

 Metapleuron pilose anteriorly and with 9 to 15 very 

 long, stout, pale bristles. Metanotal slopes bullose and 

 densely long pilose; lateral and ventral metasternmn 

 with abundant, long pile. Postmetacoxal area mem- 

 branous; tegula and basalare pubescent only; squama 

 with a multiple fringe of long, crinkled pile. 



Legs: The hind femur is stout but not especially 

 thickened; anterior and middle femora slightly thick- 

 ened along the middle and base; all pile pale on fe- 

 mora, black on tibiae; bristles of hind legs pale, the 

 anterior bristles of middle femur, their posterior 

 bristles, the posterior bristles of anterior femora and 

 their posterior tibial bristles pale, others black. The 

 posterior femur bears 3 medial, apical bristles, a pair 

 of dorsomedial bristles back from the apex, 7 lateral 

 which are rather long, 8 ventrolateral bristles, and 11 

 ventral bristles. The hind tibia beai-s 2 dorsal bristles 

 quite close to the base, 3 lateral bristles, 2 ventral bris- 

 tles beyond the middle; apex with 1 dorsal, 2 lateral, 

 3 or 4 ventral, and 2 medial bristles. The medial sur- 

 face bears a brush of appressed setae extending nearly 

 to the base and continued on to the firet two tarsal 

 segments. Middle femur with 5 long, anterodorsal, 

 7 or 8 shorter, anterior bristles, 7 short posterior, and 

 12 ventral bi-istles. The middle tibia bears 5 or 6 dor- 

 sal, 2 long anterior from the middle, 3 or 4 posterior, 

 and 2 slender ventral elements in the middle; apex 

 with 2 dorsal, 2 anterior, 2 posterior, and 4 ventral 

 bristles. The anterior femur has fine, stout, short an- 



terior bristles, 3 long posterior bristles beginning at 

 the middle, and 9 long, stout ventral elements ending 

 near the middle ; this tibia bears a double row of dorsal 

 bristles containing 11 elements and 5 long, stout poste- 

 rior and 2 equally long, stout, posteroventral bristles; 

 apex with 2 dorsal, 6 ventral, 2 posterior. Tarsi end 

 with long, thin, double-ribbed pulvilli, and stout, long 

 empodium; the claws are sharp. 



Wings : The wings are subhyaline ; the costal cell is 

 not expanded but the marginal cell is closed and rather 

 strongly rippled especially in the male. The anterior 

 branch of the third vein ends before the wing apex 

 and begins a short distance from the discal cell. 

 Fourth posterior cell closed with a long stalk; second 

 basal cell ends with two veins; anal cell closed, alula 

 large ; ambient vein complete. 



Abdomen : The abdomen is cylindroid and strongly 

 tapered in the female, less so in the male ; abdomen as 

 long as wings; the first tergite is moderately swollen 

 and convex laterally. Pile of abdomen fine, setate, 

 scanty and appressed but long on the sides of the first 

 tergite. The sternal pile is fine, long and scanty; the 

 first sternite has only a few, minute hairs, very delicate 

 and short. Bristles are present laterally on the tergites, 

 scarcely reduced in strength or numbers posteriorly. 

 There are 10 pairs laterally on the first tergite and 

 slightly shorter ones are continued over its whole pos- 

 terior margin ; the submargin of the second tergite pos- 

 teriorly bears 5 or 6 pairs and its lateral middle has 4 

 bristles. Base and middle laterally of third tergite 

 with 5 bristles, its postmargin with 6. The sixth ter- 

 gite has 6 postmarginal bristles, none basally. These 

 bristles are similarly developed in the female. Seven 

 tergites present in the male, the seventh only a third 

 as long as the sixth and the eighth narrowly visible 

 laterally. Seven tergites in the female; the eighth is 

 rather long, but forms a saddle over the ovipositor, its 

 character otherwise like the remaining tergites. Male 

 terminalia large, conspicuous, clubbed and obtuse, not 

 rotate ; the internal parts are exposed below. Superior 

 forceps deeply cleft laterally. Female terminalia short, 

 obtuse, as wide dorsally as laterally ; the terminal piece 

 bears only stiff hairs. 



Distribution : Neotropical : Oratopoda gayi Macquart 

 (18.38). 



Genus Threnia Schiner 



Figures 311. 777, 1476, 1485, 2220, 2450, 2452, 2502 



Threnia Schiner, Verb, zool.-bot. Ges. Wien, vol. 16, p. 674, 1866. 

 Type of genus : Asilus carl)onaria Wiedemann, 1828, by 

 original designation. 



These are small or medium size flies with dark colora- 

 tion. The head is nearly circular from the anterior 

 aspect and the gibbosity of the face is prominent, 

 abruptly developed and includes at least the ventral half 

 of the face. Facial bristles are long and numerous and 

 the antenna is elongate and slender with a microseg- 

 ment. The male terminalia large but obtuse and club- 



