114 COLEOPTERA OF NORTH AMERICA. 



wings wanting, and the abdomen greatly elongated ; the hind 

 coxae also become so prominent, as to leave the genuine first 

 ventral segment (invisible in all other Elateridse) free ; following 

 this are the usual five equal to each other, then the sixth, equal 

 to the fifth, but rounded at tip, and followed by a prominent ob 

 tusely triangular seventh (really the eighth) ventral segnienlJ 

 of these, all but the last two are margined behind with mem 

 brane. 



Antennae long, serrate, 11-jointed. Aplastus. 

 Antennae short, in the males pectinate ; 



Antennas 11-jointed. Plastocerus. 



Antenna? 12-jointed. Euthysanius. 



Fam. xxxvl— cebrionid ae. 



Mentum corneous, quadrate ; ligula distinct, without para- 

 glossae. 



Maxillaa exposed at base, with two lobes (in our geuera). 



Antennas inserted under the frontal margin, 11-jointed, 

 serrate. 



Head not deflexed ; eyes convex rounded. 



Labrum closely connected with the front, slightly emar- 

 ginate, transverse; mandibles (in our genera) slender, long 

 and prominent, leaving an open space between them and the 

 mouth. 



Prothorax with the side pieces not separate ; coxal cavi- 

 ties large, rounded, open behind ; prosternum very short, 

 prolonged behind into a spine. 



Mesosternum short, oblique, excavated to receive the pro- 

 sternal spine; side pieces attaining the coxaa. 



Metasternum short, pointed in front ; side pieces narrow 

 in Cebrio, wide in Scaptolenus, epimera visible. 



Elytra covering the abdomen in the males, sometimes 

 shorter in the females; epipleurae very narrow behind; wings 

 wanting in the females. 



Abdomen with six free ventral segments. 



Anterior coxae large, globose, without trochantin; middle 

 coxae rounded, with a small trochantin ; hind coxae trans- 

 verse, dilated into a plate, partly protecting the thighs. 



Legs sub-fossorial ; anterior tibiae more or less dilated or 

 expanded at the apex ; terminal spurs large; tarsi 5-jointed, 

 not lobed (in our genera) ; claws simple, onychium none. 



'i 



