312 " GEO. H. HORN, M. D. 



these give the species a peculiar appearance. The prosternum is 

 elevated at tip and subconically protuberant, suggesting an affinity 

 with Tliiihjcra and Focadius, with which there is otherwise very little 

 resemblance. It may bo called a glabrous Epiu-aea with protuberant 

 prosternum with the anterior tarsi alone dilated. 



O. qiiadricollis n. sp. — Elongate, parallel, piceo-rufous, elytra nearly 

 black, moderately shining, glabrous. Head concave, minutely and sparsely 

 punetulate, rufous. Antennae rufous, club darker and longer than the funicle. 

 Thorax quadrate, very slightly narrower posteriorly, apex feebly emarginate, 

 sides feebly arcuate and narrowly margined, base slightly arcuate, disc feebly 

 convex, anteriorly transversely flattened, rather finely punetulate, color rufous. 

 Elytra parallel, very narrowly margined, apex obtusely truncate, disc with a 

 feeble oblique impression from the humeri toward the suture, surface sparsely 

 punetulate, punctures finer near the apex. Body beneath piceous, sparsely 

 punetulate, abdomen more coarsely punctured and sparsely pubescent. Length 

 .10 inch ; 2.6 mm. (PI. Ill, fig. 24). 



The male has the small terminal abdominal segment. 

 One specimen, Colorado, (Morrison). 



I»IEL,IG£THEN Steph. 



Labrum very feebly prominent. Antennae with an abrupt three-, 

 jointed club, the grooves deep and nearly parallel. Point of pro- 

 sternum free, overlapping the mesosternum. Elytra truncate at apex, 

 pygidium exposed. Tarsi dilated, claws simple or dentate. Tibiae 

 serrate or finely denticulate. Last ventral segment with deeply im- 

 pressed, semicircular line on each side, usually in great part concealed 

 by the retraction of the segment. 



There does not appear to be any additional segment in the male, 

 nor any special sexual characters. The nearly concealed labrum, all 

 the tarsi dilated, and the impressed line of the last ventral segment 

 distinguish this genus from any other in our fauna. The species are 

 extremely difficult to define, there appears to be a degree of variation in 

 sculpture within specific limits which is very confusing. 



The following table defines such as I have been able to separate 



satisfactorily. 



Claws simple. Clypeus scarcely emarginate. 



Anterior tibise serrate, the middle emarginate externally StevtlS. 



Anterior tibise finely denticulate, the middle simple. 

 Thorax with the margin distinctly explanate. 



The explanate margin extending from base to apex rufiinaiiUS. 



The explanate margin not attaining the base iniltattis. 



Thorax very narrowly margined, the margin not explanate..semiuuluni. 

 Claws toothed at base. Clypeus rather deeply emarginate. 



Anterior tibise coarsely serrate. Thoracic margin very narrow piuguis. 



