114 



UNITED STATES NATIONAL MUSEUM BULLETIN 2 24 



it is at least three times the length of the first two seg- 

 ments combined. Base of third segment bulblike or 

 pyrif orm ; the distal portion is attenuate and stylelike, 

 or the whole segment may be gently tapered to the apes. 

 The style has an apical, bristly spine. First segment 

 with a few, short setae ventrally, the second with longer, 

 bristly setae ventrally and dorsally. 



Head, anterior aspect : The width of the head is V/s 

 times the height. Face below antenna is less than one- 

 third the head width. The face is pubescent with dense 

 pile beginning at or just beneath the antenna; the 

 pile is long, extended horizontally forward, or matted, 

 appressed and more or less extended downward. The 

 pile is composed of slender, slightly flattened hairs in 

 some species ; in others it is composed of large, ranked 

 rows of exceptionally broad scales, attenuate basally, 

 often notched apically. The subepistomal region is 

 short, small, concave, bare, and only slightly oblique. 

 The front is long and wide, densely pale pubescent or 

 pollinose, with a submarginal row of bristly hairs in- 

 cluding 1 or 2 weak, pale bristles. The front is greatly 

 widened, the vertex is still wider, not quite half the 

 head width, deeply excavated, with slanting sides. The 

 ocellarium is of only moderate width and height ; it has 

 large ocelli and between them 2 or 3 pairs of slender 

 hairs. Anterior eye facets very strongly enlarged. 



Thorax : The thorax is everywhere densely, minutely 

 pubescent or pollinose; the mesonotum is three-fourths 

 as high as long. Pile of the mesonotum is very scanty ; 

 acrostical bristles are absent; there is a row of short, 

 appressed, poorly differentiated dorsocentral bristles 

 which remain short but are somewhat more erect pos- 

 teriorly and are few in number; anterior half of meso- 

 notum laterally with a few scattered, coarse hairs more 

 abundant along the lateral margin. Humerus with 5 

 or 6 short, pale hairs. The mesonotum bears the follow- 

 ing complement of long, rather slender bristles : 1 noto- 

 pleuron, 1 suprapostalar, 1 or 2 postalar, and 4 to 9 

 pairs of long, but usually more slender scutellar bristles. 

 Scutellum flat and densely pollinose, with rectangular 

 rim and apilose and a basal crease. Propleuron widely 

 fused and broad across the middle ventrally ; the pro- 

 notum composed of a single ridge and with a row of 

 7 or 8 slender, bristly hairs; the ventral elements are 

 without pile but the lateral portion has a tuft of long, 

 fine hair and the whole posterolateral border has a 

 vertical fringe of conspicuous, long, coarse pile, especi- 

 ally long and matted in front of the humerus. Sterno- 

 pleuron with pile only posteriorly where there are 4 or 

 5 hairs ; mesopleuron with a narrow dorsal and posterior 

 band of bristly pile without well developed bristles; 

 pteropleuron and hypopleuron apilose; metapleuron 

 with a vertical row of long, numerous, slender bristles; 

 lateral slopes of the metanotum pubescent only ; lateral 

 and ventral metasternum also pubescent only, post- 

 met acoxal area membranous and pubescent. 



Legs: The femora are stout without being swollen; 

 their tibiae slender throughout and nearly as long as 



the femora. All the femora densely pubescent with 

 scanty, appressed, bristly pile dorsally ; tibiae pubescent 

 laterally and to some extent anteriorly and posteriorly. 

 The following complement of stout, sharp, somewhat 

 curved bristles is present: on the hind femur 11 lateral, 

 4 dorsolateral beginning at the outer third, 2 dorso- 

 medial near the apex, with the outer element doubled, 

 3 to 5 ventrolateral on the outer fourth, at least 4 ven- 

 tral distributed chiefly through the middle and 4 quite 

 long, bristly hairs vent romedi ally on the basal half ; this 

 tibia has 3 strong, long, dorsomedial confined to the 

 basal half, 2 dorsolateral near the base, 4 lateral, 5 

 strong ventral bristles. Middle femur with an anterior 

 dorsal tuft of 4 bristles near the outer third and with 2 

 or 3 similar posterodorsal bristles near the outer third, 

 and with 8 to 10 ventral bristles partly anterior and 

 partly posterior. Its tibia has 5 anterodorsal bristles, 

 long and stout, 3 shorter posterodorsal, 6 to 8 longer 

 posteroventral, 2 long anteroventral, besides 3 shorter, 

 more slender anterior bristles. Anterior femur with 7 

 posterodorsal bristles; the first is placed just before the 

 middle, the last subapical and matched by an antero- 

 dorsal bristle; ventral surface with an anterior and 

 posterior row of long, bristly hairs. Its tibia has an 

 anterodorsal bristle near the base, 3 posterodorsal, 3 

 conspicuous, long, posteroventral, besides 3 short, pos- 

 terior bristles. Apex without spine ; all basitarsi slen- 

 der, a little longer than the next segment and with long 

 apical bristle. Tarsi end in long, sharp, gently curved 

 claws; the pulvilli absent, the empodium bristlelike and 

 about three-fourths as long as the claw but less than 

 half as long on the anterior tarsus. 



Wings : The marginal cell is widely open ; the ante- 

 rior branch of the third vein is gently sinuous; second 

 submarginal cell a little widened anterobasally, flared 

 apically; first and second posterior cells widely open, 

 fourth posterior and anal cells closed with a short stalk ; 

 middle end vein of the second basal cell short to long. 

 Alula a little wider than the costal cell ; ambient vein 

 complete. 



Abdomen: The abdomen is strongly tapered at the 

 base, almost as wide as the mesonotum ; it is sometimes 

 flattened on the basal tergites or again strongly convex ; 

 the terminal portion of the abdomen is cylindroid. 

 Males and females each with eight tergites ; in each the 

 eighth is three- fourths as long as the seventh. Pile of 

 the abdomen is short, fine and appressed, erect on the 

 terminal segments ; almost the whole surface is densely 

 pollinose; sides of the first tergite with numerous, long, 

 coarse hairs and slender bristles. Male terminalia ob- 

 tusely conical, not rotate; the epandrium not cleft. 

 What appears to be the gonopod protrudes apically a 

 short distance beyond and immediately beneath the 

 epandrium with a minute proctiger between. Female 

 with 4 pairs of long, large, exceptionally blunt, scoop- 

 like spines, and without accessory bristles below, al- 

 though there is some short pile. Eighth sternite ex- 

 tended beyond the corresponding tergite in a broad, 

 scooplike, blunt process. 



