THE CARRION BEETLES. 



273 



Horn. — "Synopsis of the Silphida? of the United States with 

 reference to the Genera of other Countries.'' in Trans. Amer. 

 Ent. Soc. VIII. 1880. 219-322. 



Nearly 900 species of Silphidae are knowo, 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 TBIBES OE SILPHID-E. 



a. Hind coxae simple. 



6. Front coxae more or less transverse at base and with trocbantin. 

 c. Front eoxal cavities open behind. 



fj. Hind coxae contiguous ; larger. 10 or more mm. 



Tribe I. Silphixi. p. 273. 

 (7(7. Hind coxae separated; eyes wanting: smaller, not over 2 mm. 



Tribe II. Pixodttixi. p. 277. 

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



Tribe IV. AxisoioArixi, p. 2S4. 

 &6. Front coxa? eylindric-conic. without trocbantin. the cavities closed 

 behind: length less than 6 mm. Tribe III. Cholevixi. p. 27S. 

 '/a. Hind coxae with lamina? or plates; size very small, not over 2 mm. 



Tribe V. Clavibexi. p. 291. 



Tribe I. SILPHIXI. 



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?. 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 GE^sEBA OF SILPHIXI. 



a. Antenna? ten-jointed. The last four joints forming an abrupt club : mid- 

 dle coxa? widely separated. I. Xecrophorus. 

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



~b. Middle coxa? moderately separated: front coxal cavities widely open 

 behind: elytral stria?, if present, not punctured. II. Selpha. 



£>£>. Middle coxa? narrowly separated or contiguous: front coxal cavities 

 narrowly open : elytral stria? with distinct impressed punctures. 



III. Xecrophiles. 



I. Xecrophorus Fab. 1775. (Gr.. "a dead body - bearing. ") 

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



