296 GEO. II. HORN, M. D. 



pressed space piceous. Elytra broader toward the apex, the margin of which is 

 explanate and rather strongly toothed, the suture slightly retracted; disc with 

 ten rows of punctures, the first pair separated from the others by a strong smooth 

 costa extending from the basal margin to the apex, a fainter costa also exists at 

 the usual position of the third costa. Length .30-.32 inch : 7.5-8 millim. 



This species extends southward from Arizona to Mexico and Central 

 America. It may possibly be described under an older name from the 

 latter countries, but at the time Crotch described the species we were un- 

 able to satisfy ourselves that this was the case. 



O. scapularis Oliv. — Robust cuneiform, black, thorax in great part and 

 humeral angles of elytra red. Vertex punctured. Thorax widest at base, sides 

 arcuate or feebly subangulate, disc convex, slightly depressed posteriorly with the 

 ante-scutellar transverse ridge, surface coarsely and deeply punctured, color red, 

 a median piceous space. Elytra serrulate at apex, ten rows of punctures, each 

 elytron tricostate, the second and third costae separated by four rows of punc- 

 tures. Legs black, femora at basal third sometimes red. Length .22-.2Sinch; 

 5.5-7 millim. 



Occurs from the Middle States to Arizona. The Eastern specimens 

 are always smaller and have a darker thorax. 



O. notata Oliv. — Very like the preceding species in form, but differs in the 

 thorax being more regularly convex with scarcely any trace of posterior fiatten r 

 ing, and the dark space of the surface is limited to a well defined central spot. 

 The elytra are entirely black, and the punctures of the rows are 'less deep and 

 less approximated, and the rows themselves less crowded together. Length .24- 

 .26 inch; 6-6.5 millim. 



Occurs in Georgia and Florida. 



O. bicolor Oliv. — Form rather slender, beneath bright red, head, antennae, 

 elytra and legs black. Vertex sulcate. Thorax very little wider at base, sides 

 obtusely subangulate, disc convex with scarcely any trace of posterior depression, 

 cribrately punctured. Scutellum red. Margin of elytra serrulate, disc punc- 

 tured and costate as in scapularis. Body beneath bright red. Legs black, the 

 bases of the femora usually red. Length .24 inch ; 6 millim. 



This species differs also from the others in having the second joint of 

 the antennae fully as large as the third. It is also less cuneiform, ap- 

 proaching collaris in shape. 



Occurs in the Middle and Western States. 



O. dorsalis Thunb. — Black, thorax and elytra reddish yellow, the latter 

 with a common sutural piceous vitta. Vertex coarsely punctured. Thorax wider 

 at base, sides arcuate, disc cribrately punctured and with faint depression pos- 

 teriorly. Elytra striate and costate as in scapularis, margin finely serrulate. 

 Length .24-.26 inch ; 6-6.5 millim. 



The only variation in this species is in the width of the sutural vitta. 

 This is usually broader behind, sometimes it is very narrow and parallel, 

 and still more rarely wider at the base. 



Occurs in the Middle and Southern States. 



