286 THOMAS SAY FOUNDATION 



second, reaching five-sixths of the way to the vibriss^e, 

 which are at the oral margin; arista long-plumose 

 for about two-thirds of its length ; f acialia black, mid- 

 dle of face gray or slightly yellow; palpi and pro- 

 boscis black, ordinary; bucca one-fourth the eye- 

 height, with black hairs, which distinctly extend back 

 of the metacephalic suture; back of head with three 

 rows of black hairs, a few whitish hairs in the middle, 

 not conspicuous below. 



Thorax densely gray pollinose, with the usual 

 three to five black stripes; ps dc tM^o large and two 

 small; ant acr distinctly developed; prsc one pair 

 medium; stpl three; scutellum with three marginals 

 (intermediate small) one preapical of moderate size 

 and no apicals. 



Abdomen gray pollinose, tessellated, with a 

 median black stripe; fourth segment red in ground 

 color except along the base; first and second seg- 

 ments with only lateral bristles; third with median 

 marginal pair and fourth with marginal row of about 

 14, diminishing on the sides; fifth sternite yellow, the 

 sides not divergent, forming a pair of tapering and 

 pointed tips which stand up conspicuously, each bear- 

 ing a few black hairs apically. 



Hypopygium yellow; basal segment covered 

 with yellow pollen, bearing a subapical row of bris- 

 tles ; second segment also with yellow pollen and bear- 

 ing a few hairs, of which one pair are bristly ; forceps 

 yellow, becoming black near the tips; viewed from 

 behind the free part is narrow and necklike at the 

 base, diverging and widening rapidly further on, end- 

 ing in a rather blunt point. Viewed from the side 

 there is a rather distinct angle behind, a little before 

 the tip and one in front still nearer; accessory plate 

 yellow, triangular, the hind margin thin and semi- 

 transparent; posterior clasper brown toward the tip, 

 straight, bearing a moderate hook at the apex; an- 

 terior clasper long, erect, yellow, strongly bent near 

 the middle, the tip black, flat, straight, sharp in pro- 

 file; penis apparently single- jointed, yellow, the basal 



