8CUDDER.] CANADIAN POSSIL INSECTS. 41 



been mainly neglected in the descriptions of our native species. It is in 

 these that its close affinity to B. geminatus appears, but from which it 

 differs in points which distinguish it as clearly as B. americomus and B. 

 kirbyi differ from each other, but by no means . so sharply as either of 

 these differ from each other. In the present fossil species the sculpture 

 of the upper surface of the body is a clean and sharp, close, deep and deli- 

 cate, uniform set of circular punctures, differing from those of B. geminatus 

 (PL II, figs. 9, 10) only in their being less coarse and less distant, differ- 

 ences only observable under a strong lens. In the two other living species 

 referred to, the punctures are more or less confused in a transverse direc- 

 tion, at least upon the elytra, and are duller, less deeply impressed, and 

 more distant. The fossil species differs from B. geminatus in the entire 

 absence of the very slight median sulcus or stria of the prothorax, though 

 the sulci of the elytra do not differ. The only other difference observed 

 is in the puncturing of the abdominal segments, which is more distant and 

 feeble in the fossil than in B. geminatus, while that of the tibise is distinctly 

 •obscure, producing a blurred and subdued sculpture not seen in the 

 modern form. * 



Breadth, 5""" ; length of thorax, 2™ ; probable length of body, 



n.Kmm 



The specimen is preserved at the edge of a fine-grained clay nodule, and 

 has thereby lost the hinder extremity of the body, but its parts are 

 remarkably preserved, the chitine as clear as in life, but with the loss of 

 ■all. the pile which clothed the p^rts ; the chitinous shell can be raised from 

 certain parts, where the sculpturing of the surface is seen to have left its 

 ■cast in the fine clay as in the most delicate wax, though showing not the 

 remotest trace of the dermal hairs. 



Byrrhus geminatus occurs on the shores of Lake Superior, in Canada 

 West, and in New Hampshire. 



Green's Creek, Ottawa River. — H. M. Ami and A. E. Barlow, 1886. 



Family NITIDULID^. 



Peometopia Erichson. 



Prometopia depilis. 



Frometopia depilis Scudd., Rep. Prog. Geol. Surv. Can., 1875-1876, 278-279 

 (French ed., 308-309) (1877) ; Id., Tert. Ins. N. A., 500, PI. ii, 

 fig. 29 (1890). 



This beetle appears to belong to the Mtidulidse, but where it should be 

 .generically located is a matter of some doubt. It resembles most among 

 our American forms the genus in which I have provisionally placed it. 



