466 BULLETIN 63, UNITED STATES NATIONAL MUSEUM. 



and nearly closed, margins fringed with very small setse. Inferior 

 membrane not visible. 



Hahitat. — Kansas (George Horn) : Colorado (Denver, April, H. 

 Soltau) ; Wyoming (Cheyenne. June and July, Hubbard and 

 Schwarz). 



Number of specimens studied, 34. 



Type in the Horn collection. 



Type-locality. — Kansas. 



Salient type-characters. — Thoracic margin acute, not foliaceous nor 

 suddenly formed, not deeply emarginate at ajDex. Elytral margin 

 acute, feebly reflexed, and not attaining the apex; disc flattened, and 

 never concave. Epipleural limits distinctly defined (Horn). 



Diagnostic characters. — The thorax is distinctly wider than long, 

 the apical emargination is shallower and broader, the elytral disc is 

 flat or feebly convex, and the apices never caudate; the margin does 

 not reach the apex. The epipleura? are usually well defined and 

 even feebly convex. 



From contusum it differs in the shalloAver apical emargination of 

 the prothorax, and by the elytral margin not reaching the apex. The 

 prothoracic margin is distinctly narrower. 



It is recognized from elongatvin by the shorter and broader form 

 and by the elytral margin not attaining the apex. 



From depressum by the wider thoracic and elytral margins, and in 

 not having the marginal line reaching the apex. 



Planum is undoubtedly very closely related to contusum and a 

 very large series might show it to be simply a subspecies. I deem 

 it best at present not to unite the two until further collecting has 

 been done. The explanate thoracic margin varies in Avidth and the 

 marginal line is often indicated to apex by a line of asperities. 



General observations. — The mentum is moderate, middle lobe more 

 or less semicircularly arcuate anteriorly from the subangulate sides. 

 The apex may be subtruncate and the sides straight and oblique; 

 surface feebly convex and more or less obsoletely foveate laterally. 



Prosternum and mesosternum as in contusi/m. In a few speciuiens 

 there is a very slight tendency for the prosternum to become feebly 

 prominent posteriorly. 



The abdominal process is rather small and nearly quadrate, its 

 width is slightly less than the length of the post-coxal portion of 

 the same segment, the latter is about equal to the third in length; 

 the second is one-fifth of its length longer than the third, the latter 

 scarcely twice as long as the fourth. 



The abdominal and metasternal salients are equal in width. 



The metasternum lateralh^ between the coxre is short, in length 

 about equal to the width of a mesotibia at middle. 



