476 BULLETIN 63, UNITED STATES NATIONAL MUSEUM. 



Ventrolateral surfaces. — Body somewhat elongately triangular, 

 obliquely truncate laterally at base, quite acute at the internal mar- 

 gins of valves in the median line at base; surface lines straight when 

 viewed longitudinally, evenly convex from side to side, smooth and 

 shining. Submarginal groove well defined beneath the feebly ex- 

 planate external border of the dorsal plate, terminating at the apical 

 margin. Internal margins of the valves contiguous in basal four- 

 fifths: fissure narrowly fusiform in apical fifth, margins finely setose, 

 inferior membrane not visible. 



Hahitat. — Texas (Mobeetee, July, H. S. Barber) ; Colorado (Pueblo, 

 October 2T, H. Soltau ; Colorado Springs, Greeley, June, elevation 

 6,000-7,000 feet, Wickham; Fort Collins, Bellevue, West Las Animas, 

 ■\Vickham) ; Kansas (Wallace County, elevation 3,000 feet, F. H. 

 Snow; Rice County, Clark County. June, elevation 1.9G2 feet, F. H. 

 Snow) ; Nebraska ; South Dakota (Alexandria). 



Number of specimens studied, 40. 



Type destroyed. 



Type-locality. — "Arkansas at the Rocky Mountains," (Say.) 



Salient type-characters. — Margins of the thorax and elytra broadly 

 f oliaceous and strongly reflexed ; basal angles of the prothoracic mar- 

 gins projecting strongly backward over the basal angles of the elytra. 



Diagnostic characters. — Distinct from all other species as indicated 

 by the salient type-characters. 



The concaritm of LeConte is simply a larger, longer, and narrower 

 form, with the broad elytral margins more suddenly and almost 

 perpendicularly reflexed. 



General ohser rations. — The mentum is moderate in size and vari- 

 able. The middle lobe may be more or less arcuate anteriorly, or 

 truncate, evenly slightly emarginate at apex; sides more or less 

 straightened, and converging anteriorly. The form anterior to the 

 lateral and subbasal angles is subparabolic or subtriangular. 



Prosternum arcuate antero-posteriorly and somewhat prominent 

 ventrally with the coxae; sometimes more or less oblique and feebly 

 compressed posteriorly. 



]\fesosternum variable as to the degree of obliquity: usually sub- 

 vertically arcuate and broadly, feebly concave. 



The abdominal process is subquadrate and just the least transverse, 

 and equal in width to the length of the thii'd segment; tlie ])ost-coxal 

 part of the first segment about equal in length to that of the third; 

 the second is twice as long as the fourth : tlie third is about one-third 

 of its lengtli shortei- than the second. 



The abdominal aud metasternal salients are quite equal. 



The metasternum laterally between the coxa? is about equal in 

 length to the width of a inesotibia at apex. 



