324 GEO. H. HORN, M. D. 



Our species are more numerous than in any of the preceding groups 

 and may be distinguished as follows : 



Thorax densely clothed with white pubescence ; surface color concealed. 



Elytra black, an elongate triangular sutural space clothed with white. .Ulltoi. 

 Thorax sparsely or not clothed with cinereous pubescence; surface color always 

 visible and black. 

 Elytra black with rufous spots on spaces. 



Suture depressed. Rufous spot median touching the lateral margin. 



bivuliieratiis. 

 Disc of elytra flat; suture not depressed. 



Thorax with median line distinctly impressed at base; elytra more 

 rufous than black. 



Hind legs black limbatu*. 



• Hind legs pale rufous discolor. 



Thorax with median line; elytra more black than rufous. 



Elytra with rufous spot near outer apical margin cruentatus. 



Elytra black. 



Hind femur and tibia bicolored itigriiius. 



Hind legs entirely black pruiuiiiiE*. 



O. Ullcei, n. sp. — Black, densely clothed with white pubescence, elytra 

 with broad lateral space clothed with black pubescence. Head broadly oval, 

 black, opaque, densely punetulate and clothed with whitish pubescence, epis- 

 toma black. Antennae half the length of the body, pale rufous, serrate. Tho- 

 rax one-half wider at base than long, sides moderately arcuate and rapidly 

 narrowed in front, apex truncate, angles broadly rounded, base with moderate 

 median lobe rounded at tip, on each side feebly sinuate; surface coarsely punc- 

 tured and densely clothed with silvery white hairs. Scutellum sub-quadrate, 

 bifid at tip, clothed with white pubescence. Elytra scarcely wider at base 

 than thorax, sides moderately arcuate and gradually narrowed to tips which 

 in each are broadly rounded, surface striate, striae distantly punctured, inter- 

 vals flat very densely punetulate and densely clothed at the sides with very 

 black pubescence, and with a triangle of silvery white hairs common to both 

 elytra. Body beneath black, densely clothed with silvery white hairs. An- 

 terior and middle legs rufous, hind legs black. Pygidium broadly oval, 

 densely clothed with white and on each side a round black spot. Terminal 

 abdominal segment with a black spot on each side of middle. Length .20 

 inch; 5 mm. 



One of the most distinct species in our fauna, and at the same time 

 with an unique style of vestiture. The lateral black space begins at 

 the base of the sixth stria and extends obliquely to the tip of the 

 suture, a narrow epiplural space is, however, white ; the white space 

 is thus confined to an elongate triangle common to both elytra. 



Dedicated with great pleasure to Mr. H. Ulke, who has at all times 

 placed at my disposal any species for study contained in his cabinet. 



Collected in Arizona. 



