ARTHROPODS 



received by the mesosternum, al- 

 though it may be prolonged so as 

 to meet the mesosternum. 

 P. Posterior coxae separated. 

 Q. Body very depressed ; middle 

 cavities not closed externally by 

 a meeting of the mesosternum 

 and metasternum . . Cucujidae. 

 MM. Anterior coxae conical, and project- 

 ing prominently from the coxal cavities. 

 N. Posterior coxae dilated into plates 

 partially protecting the femora, at least 

 at their bases. 



O. Antennae with the last three seg- 

 ments forming a large club. 



Dermcstidae. 

 KK. Abdomen with six or more ventral seg- 

 ments. 



L. Anterior coxae either globular or con- 

 ical. 

 M. Anterior coxae globular. 



N. Prosternum prolonged behind, form- 

 ing an acute process moving in the 



mesosternum Elateridae. 



NN. Prosternum not prolonged behind. 



. .Leptinidae. 

 MM, Anterior coxae conical. 



N. Posterior coxae more or less conical 

 and prominent, at least internally, not 

 covered by the femora in repose. 

 O. Posterior coxae widely separated. 

 P. Eyes wanting or inconspicuous. 

 Silphidae. 

 OO. Posterior coxae approximate. 

 P. Antennae gradually thickened, or 

 clavate; posterior tarsi not wid- 

 ened Silphidae. 



