52 COLEOrTERA OF NORTH AMERICA. 



covered by the elytra. Posterior coxae contiguous, dilated into 

 lamina? covering the posterior thighs ; trochanters not prominent. 

 This tribe consists of very minute species, living in decomposing 

 vegetable matter. On account of the extreme minuteness of the 

 insects, the generic descriptions have been very imperfect, and 

 indeed inaccurate ; it is only in the works of Redtenbacher, La- 

 cordaire, and Duval that the full characters have been detailed. 

 This fact will account for the confusion regarding the genus Ster- 

 nuchus, established by me in Agassiz's work on Lake Superior, 

 which I afterwards united with Clambus. 



Club of antennae 3-jointed ; coxal plates narrow, dilated internally (body 



glabrous). Empelus. 



Club of antennae 2-jointed; coxal plates very broad (body usually pubes- 

 cent) ; 

 Antennae 10-jointed ; abdomen with 6 ventral segments. Calyptomerus. 

 Antennae 9-jointed ; abdomen apparently with 5 ventral segments. 



Clambus. 



The type of Empelus is Litochrus brunnipennis Mann, from 

 Sitkha. Having the anterior coxae contiguous, transverse, coni- 

 cal, and prominent, it cannot be placed in the family Phalacrida?, 

 to which Litochrus belongs, but seems to me to be a very obvious 

 connecting link between Agathidium and Clambus. To Calyp- 

 tomerus belongs Clambus oblongulus Mann., also from Russian 

 America. 



Sub-Family II.— BRATHINIDAE. 



But one genus, Brathinus, is known of this sub-family, which is 

 remarkably distinguished from the genuine Silphidae by the pro- 

 minent conical middle coxae. The two species known to me are 

 found about grass-roots in wet places, from Lake Superior to 

 Nova Scotia, and are small shining insects, of graceful form, less 

 than one-fifth of an inch long. 



The head is oval, strongly constricted behind, with the front 

 concave ; eyes moderately prominent, oval, somewhat coarsely 

 granulated ; the gula behind the mentura is deeply channelled ; 

 the maxillary palpi are long and slender, the third joint is one- 

 half the length of the second, and the fourth is longer than the 

 second ; the labial palpi are moderately short, with the last joint 

 a little longer. The antennae are slender, almost filiform, with 



