192 ■ BULLETIN 63, UNITED STATES NATIONAL MUSEUM. 



basal angles rectangular. Elytra elongate, densely punctate, punc- 

 tures on the dorsum subseriate, laterally and on the apex trans- 

 versely confluent and muricate (LeConte). 



Diagnostic characters. — Easily separated from ohscura and sulci- 

 pennis by its obsolete striae and finely muricate punctuation, by the 

 comparatively more elongate and narrower form. Even in a moderate 

 series the three races are united by an ample number of examples 

 exhibiting all degrees of intermediate sculpturing. 



The mentuni has the middle lobe moderate, and about as Avide as 

 long; sides more or less arcuate; apex also rounded, slightly reflexed, 

 truncate or feebly emarginate; surface strongly punctate, slightly 

 prominent along the median line, feebly and broadly concave laterally 

 and clothed with stiff hairs that curve forward. 



The prosternum is triangularly dilated behind the equator of the 

 coxse, and more or less protuberant ventrally with the same; pos- 

 teriorly compressed, vertically truncate, and more or less produced; 

 at times it is arcuately declivous. 



Mesosternum quite vertically declivous or oblique and more or less 

 concave. 



The abdominal process is subquadrate, about one-sixth of its width 

 wider than long, its width is also equal to the post-coxal portion of 

 the same segment. The second segment is a little more than twice as 

 long as the fourth; the third is about equal to the post-coxal part of 

 the first ; the fourth is about one-third of its length shorter than the 

 third. 



The abdominal salient is about a sixth of its width greater than the 

 same of the metasternal process. 



Metasternum laterally between the coxae is as long as the width of 

 a mesotibia at apex. 



The tibial grooves of the femora are not entire. Those of the pro- 

 femora are quite broad, the floors rather feebh' concave, smooth and 

 impunctate; the margins are strong and gradually converge to meet 

 just before attaining the base, the anterior is more or less dentately 

 laminate, forming an obtuse (female) or an oblique tooth (male). 



On the mesofeuiora the grooves become evanescent at internal third, 

 but are well defined externally, floors feebly concave and smooth. 



The metafemora have the grooves evanescent at middle without con- 

 vergence of the sides, which are well marked externally. 



The tibia' are very densely muricate. Each protibia is moderateh^ 

 compressed and (piite strongly carinate externally in basal half, where 

 it is also more or less arcuate; the carina is smooth and at the middle 

 of the protibia becomes the anterior boimdary of the tarsal groove, 

 where it also becomes muricate to the apex. The tarsal groove is 

 quite strongly defined and its floor is glabrous and impunctate, open- 



