266 THOMAS SAY FOUNDATION 



thirds its length; palpi and proboscis black, the for- 

 mer slender; bucca one-fifth the eyeheight, clothed 

 mostly with pale hairs ; back of head with three rows 

 of black hairs above, narrowing to one opposite the 

 lower part of the eye; the middle part and below 

 clothed with whitish hair. 



Thorax grayish white pollinose, with three to five 

 very black stripes, the middle one narrowed in front ; 

 the submedian gray stripes undivided; ps dc four, 

 successively smaller; ant acr about 3 pairs, one quite 

 large pair just before the suture; prsc one; stpl three; 

 scutellum with two marginals, both long, preapicals 

 scarcely perceptible, one pair smallish apicals. 



Abdomen subshining in some lights, strongly tes- 

 sellated in others, with a median black shining stripe 

 and two lateral shifting ones; first and second seg- 

 ments with only lateral bristles; third with one pair 

 median marginals and three or four laterals, forming 

 an interrupted row; the fourth with a marginal row 

 of about a dozen. Fifth sternite very much retracted, 

 practically invisible. 



Hypopygium with first segment rather small, 

 subshining, black, witliout bristles; second segment 

 globose, shining red, without bristles; forceps yellow 

 throughout their entire length, very wide in profile, 

 the apical part turned forward, ending in a broadly 

 truncate form; in profile the front edge has almost a 

 right angle where it turns near the end, while the pos- 

 terior edge is rather broadly and uniformly curved; 

 from beliind tlie broad tips are divergent. Accessory 

 plate yellow, comparatively narrow, rather long; pos- 

 terior clasper long and nearly straight, slender, the 

 tip blackish ; anterior clasper shorter, sharp and some- 

 what hooked at the tip, entirely yellow. Penis with 

 a very short yellow basal segment; distal segment 

 globose at its beginning, wholly yellow, diverging api- 

 cally into two long lateral processes whicli bear a 

 connecting margin or plate between them. 



Legs black; middle femur without comb; middle 



