48 COLEOPTERA OF NORTH AMERICA. 



Fam. vil— silphidae. 



Mentum quadrate, sometimes slightly emarginate, fre- 

 quently with a transverse piece between it and the ligula, 

 which is prominent, emarginate, or bilobed; gular suture 

 distinct. 



Maxillae with two lobes, inner one sometimes with a 

 terminal hook. 



Eyes finely granulated, sometimes absent. 



Antenme inserted under the margin of the front, behind 

 the base of the mandibles; 11-jointed, rarely 9 or 10-jointed: 

 gradually or suddenly clubbed at the apex, sometimes nearly 

 filiform. 



Prothorax with the epimera and episterna not distinct. 



Mesosternum very short, side pieces attaining the coxae. 



Metasternum large, nearly truncate behind ; episterna long; 

 epimera large, distinct. 



Anterior coxce large, conical, contiguous; middle coxae 

 oblique, not prominent, except in Brathinus; posterior con- 

 tiguous (except in the foreign genus Leptoderus), not extend- 

 ing to the margin of the body, prominent internally, rarely 

 (Clambini) laminate. 



Abdomen with six free ventral segments, except in Sphae- 

 rites, which has but five. 



Legs sometimes thick, subfossorial (Necrophorus), some- 

 times very slender (Pteroloma) ; tibiae with large terminal 

 spurs, the anterior ones of the male usually dilated; tarsi 

 usually 5-jointed ; posterior trochanters prominent, or not. 



The anomalous form of the middle coxa? in Brathinus Lee. re- 

 quires the division into two sub-families: — 



Middle eox<e oblique, not prominent. Silphidje. 



Middle coxae conical, prominent. Beathinid^. 



Sub-Family I.— SILPHIDAE (genuini). 



This sub-family contains species which live on decomposing 

 animal matter or on fungi; some species of Catops are found only 

 in ants' nests, while the wonderful genus Leptoderus, not yet found 

 in America, lives in caves; it differs remarkably from other genera 

 of the family by the long cylindrical thorax, the globose, connate 



