214 COLEOPTERA OF NORTH AMERICA. 



Our genera may be arranged — 

 Middle lobe of epistoma rounded ; mandibles toothed above ; eyes rounded. 



Triokophus. 

 Middle lobe of epistoma truncate ; mandibles not toothed; 



Hind coxae widely separated ; eyes subtransverse. Ckaniotus. 



Hind coxae approximate ; eyes emarginate. Teimytis. 



Triorophus contains four species ; three from California, and 

 one from Texas. Craniotus is found in the interior of California, 

 Trimytis in New Mexico and Nebraska. All are found on the 

 ground, under stones, &c. The intercoxal process of the abdo- 

 men is parallel in the first two genera, but triangular and acute 

 in Trimytis. Each genus may be considered as representing a 

 separate group. 



Tribe III.— THUVOBATIUTI. 



Body oval or rounded, sometimes winged ; epistoma truncate, 

 or feebly rounded ; labrum prominent, or not ; mentum very large, 

 entirely filling the gular cavity ; ligula and maxillse concealed ; 

 elytra not widely embracing the flanks of the abdomen ; prosternum 

 not adapted to the mesosternum ; metasternum sometimes elon- 

 gated ; middle coxas without trochantin, inclosed by the sterna ; 

 hind coxae approximate, intercoxal process of the abdomen acute. 

 Tarsi ciliate beneath. 



Although the unique specimens of Cryptadius and Auchmobius 

 have been lost, I am quite certain about the position of these 

 genera. 



Our genera may be thus tabulated : — 

 Eyes with distinct superciliary ridges ; 



Anterior tibiae with the outer angle prolonged ; 



Body inflated. Cryptadiits. 



Body elongate oval. Eurymetopon. 



Anterior tibiae truncate at tip. Emmenastus. 



Eyes without superciliary ridges, anterior tibiae truncate. Auchmobius. 



In some individuals, both of Eurymetopon and Emmenastus, 

 the labrum is retracted and almost concealed under the epistoma. 

 In both genera are species with and without wings ; in the former 

 case the metasternum is longer than the first ventral segment. 



To Emmenastus I would refer Eurymetojion longulum, obesum, 

 and atrum Lee. All the species of this tribe are Californian, 

 except a few Emmenastus from Nebraska, New Mexico, and 

 Texas. The winged species are found under bark of Prosopis, 

 the others under stones. 



