THE CARRION BEETLES. 273 



Horn. "Synopsis of the Silphida 1 of the Tinted States with 

 reference to the Genera of other Countries," in Trans. Amer. 

 Ent, Soe., VIII. 1880. 219-322. 



Nearly 900 species of Silphida? are known, about 125 of which, 

 distributed among- 31 genera, are from North America. Horn, in 

 his Synopsis, divided the family among six tribes. . Four of these 

 are known to be represented in Indiana, while a single species of an- 

 other may occur. 



KEY TO INDIANA TRIBES OF SILPHID/E. 



a. Hind coxae simple. 



l>. Front coxa? more or less transverse at base and with trochantin. 

 c. Front coxal cavities open behind. 



'/. ITind coxa 1 contiguous; larger, 10 or more mm. 



Tribe I. SILPHINI, p. 273. 

 <ld. Hind coxa? separated; eyes wanting; smaller, not over 2 mm. 



Tribe II. PINODYTINI, p. 277. 

 cc. Front coxal cavities closed behind; length less than 5 mm. 



Tribe IV. ANISOTOMINI, p. 284. 



hl>. Front cox;e cylindric-conic, without trochantin, the cavities closed 

 behind ; length less than 6 mm. Tribe III. CHOLEVINI, p. 278. 

 da. Hind coxa? with lamina? or plates; size very small, not over 2 mm. 



Tribe V. CLAMBINI, p. 2!)1. 



Tribe I. SILPHINI. 



To this tribe belong all the larger members of the family, the 

 distinctive characters being the open front coxal cavities and the 

 contiguous hind coxa 1 . The form is sometimes elongate, but usually 

 oval or even nearly circular : elytra distinctly, sometimes widely, 

 margined at the sides; abdomen often visible beyond the elytra. Of 

 the seven genera comprising the tribe, three are represented in In- 

 diana. 



KEY TO INDIANA GENERA OF SILPHINI. 



(i. Antenna? ten-jointed, the last four joints forming an abrupt club; mid- 

 dle coxae widely separated. I. NECROPHORUS. 

 aa. Antenna? eleven-jointed, either slender or gradually clavate. 



&. Middle coxa? moderately separated ; front coxal cavities widely open 

 behind; elytral stria?, if present, not punctured. II. SII.PHA. 



&6. Middle coxae narrowly separated or contiguous; front coxal cavities 

 narrowly open ; elytral stria? with distinct impressed punctures. 



III. NECROPHILUS. 



I. NECROPHORUS Fab. 177:". (Or., "a dead body -i- bearing. ") 

 To this genus belong- large, elongate, thick-bodied beetles, having 



