104 



UNITED STATES NATIONAL MUSEUM BULLETIN 224 



pleuron. Metapleuron with 4 long, fanlike, stout 

 bristles. Metanotal slopes micropubescent only ; meta- 

 stemal slopes with numerous, stiff hairs; metasternum 

 with a few, fine hairs ; postmetacoxal area membranous. 

 Presternum not dissociated. 



Le^s : The anterior and middle femora are short and 

 stout and moderately thickened. Hind femur relatively 

 slender with dense, appressed, fine pile. It bears a 

 dorsolateral bristle at apex, 2 dorsomedial near apex, 

 and 2 or 3 ventrolateral bristles along the middle. Its 

 tibia has 3 or 4 stout, dorsal and 3 stout, lateral bristles, 

 the apex with 7 bristles. The middle femur bears dense, 

 short setate pile, including the ventral surface, and a 

 stout, posterodorsal, subapical bristle, 3 anterior, 2 

 short, weak bristles at the base, 2 ventral bristles on 

 the basal half, and 1 ant ero ventral bristle at the outer 

 third. This tibia bears rather short, stout bristles: 4 

 dorsal, 3 or 4 posterodorsal, 4 posterior, and 4 

 posteroventral. Tibial apex with 2 dorsal, 3 posterior, 

 2 anterior (1 exceptionally long), and 3 or 4 ventral (1 

 especially long) . Anterior femur similar to the middle, 

 with stout, long posteroventral subapical, 3 weak, short 

 ventral bristles; its tibia bears 4 or 5 short postero- 

 dorsal, a like number of dorsal, 6 posterior, and 3 much 

 longer, stouter posteroventral bristles. The apical 

 circlet is similar; no tibial spine. Tarsi end in well 



developed pulvilli as long as the sharp claws, and a 

 basally stout empodium. 



Wings: The wings are rather broad, subhyaline. 

 Marginal cell closed at the margin, the end of this cell 

 bluntly rounded ; anterior branch of third vein sigmoid, 

 ending far above the wing apex ; posterior branch fur- 

 ther behind. The first posterior cell is closed with a 

 short stalk; fourth posterior cell closed with a long 

 stalk ; anal cell closed ; second basal cell ends in 3 veins. 

 The alula large; ambient vein complete. 



Abdomen : The abdomen is robust, at least as wide as 

 the mesonotum, and as long as the wings. The tergites 

 are slightly convex, the first tergite unswollen laterally. 

 Pile of abdomen, like that of the mesonotum, is ex- 

 tremely dense, microscopically short and appressed, 

 with lateral spots of pollen on each posterior margin. 

 Sternal pile short and subappressed. Bristles are ab- 

 sent except on the first tergite, on which are 3 pairs of 

 exceptionally stout bristles. Males with six tergites; 

 females with six tergites and a liplike seventh tergite 

 one-sixth as long as the preceding segment and largely 

 tucked beneath it. Male terminalia distinctly short- 

 ened, rotate one-quarter to the left. Female terminalia 

 very short, with only the prominent, divided and ap- 

 posed proctiger protruding ; no spines present. 



Distribution : Ethiopoan : Saucropogon transvaalen- 

 s^Eicardo (1925). 



Tribe Stichopogonini 



These small, pollinose flies are readily recognized by 

 the strongly divergent front and vertex and by the ab- 

 sence of pile on the lateral slopes of the metasternum ; 

 moreover, they tend to be pale in coloration, matching 

 the sand or mud flats which they frequent. The archaic 

 crossvein does not seem to be always present in species 

 of Cryptopogon White; in my series it was frequently 

 absent. For Eremodromus Zimin the figures given by 

 Zimin indicate a fly with a remarkably low, short face, 

 the antenna arising on the lower fourth or lower fifth 

 of the subglobate head. Turkmenomyia Paramonov is 

 said to have 4 very long, weak bristles on the underside 

 of the third antemial segment and to be separable from 

 Eremodromus by the longer, third antennal segment 

 and the greater height of the face. 



A relatively small tribe of almost worldwide dis- 

 tribution, with the majority of the species of the 



Stichopogonini from the Palaearctic region. The Hol- 

 arctic genus Lasiopogon Loew belongs here, and to- 

 gether with Willistonina Back their members are as- 

 sociated with vegetated areas, especially in the moun- 

 tainous portions of western America, often near water, 

 while others frequent logs or sand. Some are even 

 found on the sands of sea beaches. 



The divisions created by Bezzi (1910b) with the ex- 

 ception of Lissoteles Bezzi, are little more than sub- 

 genera. Some species of Stichopogon Loew and Toions- 

 endia Williston are among the smallest of all robber 

 flies. They reach a length of 3 mm. The largest mem- 

 bers of this tribe are found among Neopogon Bezzi, 

 Willistonina Back, and Clinopogon Bezzi. The author 

 has collected individuals of Cryptopogon White in 

 company with others of Stichopogon Loew on bay 

 shores in Australia. 



KEY TO GENERA OF STICHOPOGONINI 



1. Four posterior cells. Extremely small flies. 



Townsendia Williston 

 Five posterior cells 2 



2. Face plane or even slightly concave 8 



Face distinctly gibbous and rounded, often rather strongly 



protuberant Lasiofogon Loew 



3. The third autennal segment bears a long, slender, truncate 

 style, nearly or quite as long as the 3 segments combined ; 



third segment oval Lissoteles Bezzi 



The third segment bears a short, or long, stout, usually 

 attenuate microsegment carrying an apical spine . . 4 



