120 COLEOPTERA OF NORTH AMERICA. 



cipal distinguishing character is that the outer joints of the an- 

 tennae, though somewhat lamellate, cannot be placed closely so 

 as to form a compact club. In the position of the abdominal 

 spiracles the tribe Lucanini resembles the first sub-family of the 

 Searabaeidse, in which alone occur tribes with the pygidium en- 

 tirely covered by the elytra, as in the present family. In fact, 

 for a distinguishing character from some of the tribes, reliance 

 must be had on the large size of the mentum, and the form of the 

 antennal club. 



They form two tribes, distinguished by the form of the mentum 

 and position of the ligula. Those portions of the body in the 

 second tribe recall strikingly the form already seen in the Cara- 

 bidas, with which, however, the insects have no other resemblance. 



Mentum entire, ligula behind or at the apex of the mentum. Lucanini. 

 Jleutum deeply emarginate, ligula filling the emargiuation. Passalini. 



Tribe I.— LUCANINI. 



Ligula membranous or coriaceous, usually behind the mentum, 

 which is entire ; mandibles without a basal molar tooth, usually 

 elongated in the males ; external lobe of the maxillae unarmed, 

 penicillate ; labrum connate in the first sub-tribe, free in the other 

 two ; scutellum between the elytra ; middle coxa? somewhat trans- 

 verse. 



The species are usually large oblong insects, glabrous above, 

 sometimes cylindrical. 



Sub-tribes, all having the thorax not closely applied to the 

 elytra, are represented in our fauna as follows : — 



Ligula and maxillae covered by the mentum ; 



Anterior coxae approximate ; antennae geniculate. Lucanini. 



Anterior coxae contiguous ; antennae straight. Cekuchini. 



Ligula and maxillae not covered ; antennae straight. Sinodendrini. 



Sub-Tribe 1. — Lucaililli (genuini). 



The typical genus is represented by three large species from 

 the Atlantic States, one of which (L. elaphus), by the very long 

 mandibles of the male, resembles the stag-beetle of Europe, and 

 one from New Mexico. Of Dorcus two species are found in the 

 Atlantic States ; of Platycerus we have two eastern species, and 

 two from California and Oregon. The genera are thus distin- 

 guished : — 



