98 



UNITED STATES NATIONAL MUSEUM BULLETIN 224 



TART 1 



only a few short hairs below. Palpus clearly of two 

 segments but small, cylindrical and, excepting 3 stout 

 apical bristles with only 2 or 3 bristly hairs on the 

 terminal segment; segment 1 is hemicylindrical, exca- 

 vated and fused to the base ; segment 2 not porate. 



The antenna is attached at the upper fifth of head. 

 It is moderately elongate, the first segment nearly 

 equal or barely longer than the second. The third seg- 

 ment is a little longer than the first two combined, 

 laterally flattened, narrowed on the immediate base and 

 only slightly attenuate; on the immediate apex it bears 

 a short, terminal subsegment which is attached 

 obliquely and extended ventromedially out to form a 

 short, upturned, spoonlike structure; its open face is 

 dorsolateral and contains a minute spine. First seg- 

 ment with 2 or 3 moderately strong, long, ventral and 

 lateral pale bristles or with only a like number of stiff 

 hairs; its apex above with a tuft of stiff setae; second 

 segment with 3 long curved, oblique, stout, black 

 bristles below and sometimes with an equally stout, 

 long bristle above. 



Head, anterior aspect: Face below antenna two- 

 sevenths of head width and with parallel sides; sub- 

 epistomal area long, oblique, slightly sloping laterally 

 from the midline, and bare. The face is pubescent, with 

 a few scattered, curled, flat appressed hairs on the lower 

 half ; along the epistomal margin there is a dense fringe 

 of moderately long, fine pile directed downward among 

 which there is sometimes a pair of divergent, slender, 

 widely separated, downwardly directed bristles which 

 are wide apart and between these a pair of closely ad- 

 jacent similar bristles directed straight forward. In 

 other species there may be stiff pile sublaterally on each 

 side of the face and extending all the way to the an- 

 tenna, and as many as 8 pairs of slender epistomal 

 bristles for the most part directed straight forward. 

 The unusually short and pubescent front has 8 or 9 ap- 

 pressed setae on each side; it is very slightly wider than 

 the face, the vertex not convergent. Vertex moderately 

 excavated, with oblique sides ; ocellar protuberance con- 

 vexly rounded, moderately large, without pile or 

 bristles. Eye facets strongly enlarged centrally. 



Thorax: The mesonotum without pollen or micro- 

 pubescence but pleuron densely pollinose. Mesonotal 

 height is one-half of the length. The mesonotal pile is 

 microscopically short, scaliform, some areas setate and 

 both completely flat apressed; no differential acrostical 

 or dorsocentral bristles. Humerus with a fringe of 

 suberect, fine pile anteriorly. Mesonotal bristles are 

 present as follows : notopleural bristles absent; a lateral 

 fringe of 8 short but very stout supra alar which may 

 become as many as 10 somewhat longer, stout bristles 

 in other species; postalar pollinose, with only a ventro- 

 lateral fringe of fine pile ; scutellar margin and surface 

 with only flat appressed minute curled setae. The pro- 

 pleuron has scattered, long hairs on the lower portion 

 and on the collar and on the upper posterior section. 

 Upper half of mesopleuron with flat appressed scalose 

 pile as on the mesonotum and a few isolated hairs pos- 

 teriorly and on the anterior extension. Upper post- 



sternopleuron with a few scattered appressed setae; 

 upper pteropleuron with 5 or 6 slender, long hairs. 

 Lower post hypopleuron with some short, fine pile; 

 metapleuron with a vertical band of numerous, long, 

 quite slender, delicate bristles; metanotal slopes bullose, 

 without pile ; pubescent only ; lateral metasternum with 

 numerous long, stiff hairs on the upper section, a few 

 hairs below, the metasternum with only short scattered 

 pile ; postmetacoxal area membranous ; tegula pubescent 

 only. Presternum not dissociated. 



Legs : Anterior 4 femora quite stout, their thickness 

 evenly distributed throughout the middle; posterior 

 femur strikingly swollen and massive, especially at the 

 middle and beyond, and slightly attenuate basally; 

 femur more than 3 times as thick distally as its width 

 at the trochanters. The hind femur is covered with 

 abundant, flat appressed pile rather long dorsally, short 

 medially and laterally below. Bristles absent but the 

 ventral margin of this femur with a double row of 8 

 to 10 extremely stout, tuberculate spines enclosing on 

 either side the tibia, and extending over the outer two- 

 thirds of the femur. Hind tibia stout, arcuate and 

 without spines or bristles, though densely flat appressed 

 pilose. Middle femur with 2 short, stout bristles pos- 

 teroventrally and 2 anteroventrally near the apical 

 third ; sometimes with 3 small weak bristles anteriorly 

 near the apex. In other species there are 4 or 5 stout, 

 very sharp, rather longer bristles ventrally on either 

 side and extending back nearly to the base with 3 longer 

 anteroapical bristles, or weak bristles may be present 

 posteriorly on the apical half. Middle tibia with 2 or 

 3 weak bristles posteriorly and sometimes 2 or 3 weak 

 bristles dorsally. Anterior femora in the type of genus 

 without bristles; in other species with 2 to 4 sharp 

 ventral bristles on the basal half, its tibia may have a 

 weak dorsal row of 2 or 3 bristles, a posterodorsal row 

 of 2 posterior and 2 ventral, or may be only hairs. The 

 segments of all of the tarsi are greatly shortened but 

 this is especially true of the hind and middle tarsi. 

 Tarsi end on the first 4 legs in small, short, basally 

 thickened, moderately sharp claws in the type of genus ; 

 pulvilli and empodium as long as the claws and on the 

 hind tarsi with much larger, thick, strongly curved and 

 bluntly pointed claws; in other species the anterior 

 tarsi are not reduced but the claws are frequently rather 

 blunt; pulvilli with marginal fringe. 



Wings: The wings are of normal width; marginal 

 cell open. Anterior branch of third vein ends before 

 the wing apex. The first posterior cell is closed with 

 short stalk, the fourth closed with a long stalk; anal 

 cell closed and stalked; the second basal cell ends in 

 3 veins, the middle vein short. Alula large, extending 

 considerably beyond its attachment; ambient vein 

 complete. 



Abdomen: The abdomen is unusually wide and ro- 

 bust, in the type of genus wider than the entire thorax. 

 The tergites are very gently convex, the abdomen 

 slightly drooping; abdomen shorter than wings, the 

 pile exceedingly short and flat appressed, longer, flat 

 appressed and matted along the sides of the tergites. 



