184 ERNEST A. BACK. 



length of the first two segments taken together and bearing 

 on the inner distal half a linear depression; terminal style 

 obsolete. Face narrower above, broader and evenly swollen 

 on the lower half; mystax composed almost entirely of long 

 rigid bristles extending over the swollen portion of the face, 

 vibrissa? composed of short hairs confined to the middle of the 

 face and reaching nearly to the antennas. Ocellar tubercle 

 not prominent, with short bristles; frontal orbits with long, 

 forward-directed bristles, and the occiput with numerous 

 bristles, not confined to the occipito-orbital margins. Pro- 

 thorax well clothed with bristles. Dorsum of mesothorax 

 with short bristly hair, and with bristles on the humeri, pos- 

 terio callosities and lateral margins, — -these last forming an 

 irregular band extending from before the base of the wings 

 upwards and backwards to above the posterior callosities; 

 scutellum with a fringe of bristles on its posterior margin. 

 Pleurae nearly bare; trichostical bristles present. Abdomen 

 elongate, everywhere with short sparse microscopic hair; seg- 

 ments 1 and 2 with a lateral patch of bristles. Male genetalia 

 small, not at all club-shaped. Legs robust, everywhere with 

 short hair and longer sparse bristles which are much more 

 abundant on the front and middle tibiae; front tibiae without 

 a terminal claw-like spur; coxae clothed with stout bristles. 

 Wings proportionately broad, the first posterior cell wide open, 

 the fourth closed a short distance before the margin, the anal 

 closed in the margin. 



Type. — Dasypogon ceacus Wiedemann. 



Ospriocerus is very closely related to Stenopogon, but differs 

 from it chiefly in the third segment of the antennae being 

 longer, linear and destitute of a terminal style. * Aside from 

 Stenopogon ceacidimis Williston, its species are secondarily 

 characterized by their general black color usually relieved 

 by red or yellowish-red upon the abdomen. 



SYNOPSIS OF SPECIES. 



1. Abdomen largely yellowish-red 2. 



Abdomen wholly black initios. 



* O. diversus Williston, has a minute style. 



