228 THOMAS SAY FOUNDATION 



facials with the usual row of hairs, the lower quite 

 long; antennse black, the tliird joint 1% times the 

 second, reaching hardly three-fourths of the distance 

 to the vibrissse, which are at the oral margin; arista 

 plumose for three-fifths its length; palpi and pro- 

 boscis black, ordinary; back of head with three rows 

 of black hairs and considerable whitish beard, which 

 however is sharply limited anteriorly on the bucca by 

 the metacephalic suture; outer vertical absent. 



Thorax gray pollinose, with the usual three to 

 five black stripes, the submedian stripes divided to the 

 suture ; ps dc 4 ; ant acr wanting or quite small ; prsc 

 1 pair; stpl 3; scutellum with 2 marginal pairs and 

 one discal. 



Abdomen gray, tessellated ; first and second seg- 

 ments with only lateral bristles; third with a median 

 marginal pair and four laterals; fourth largely red 

 (usually the posterior half or more), which extends 

 to the lower side; it bears a marginal row of about 

 14 bristles, and on the under side the ends of the ter- 

 gite bear dense, long hair. 



Hypopygium red ; first segment of medium size, 

 pollinose above, generally without bristles on hind 

 edge, but occasionally with small ones; second seg- 

 ment red, shining, globose, witliout bristles; forceps 

 black, not very large, gently curved forward, in pro- 

 file the front and back edges nearly parallel, at the 

 tip the front edge is excised, leaving a tooth on the 

 hind edge ; the attached part of the forceps is covered 

 with dense, black hair. Accessory plate yellow, tri- 

 angular ; posterior clasper black, unusually stout, with 

 a sharp tip curved forward; anterior clasper black, 

 rather slender, with sharp tin; nenis largely blackish; 

 basal segment rather short, distal one small on basal 

 part, with a wide, rather thick middle, from Avhich on 

 the front side projects a concave, partly pale trans- 

 verse plate; at the tip behind is a sharp point, from 

 each side of which at its base arises a long slender 

 process directed forward. Between these arms and 

 out of a central apical cavity arise two slender proc- 



