3G6 COLEOPTERA OF NORTH AMERICA. 



the maxillfe, ligula promineut; antennjB 10 jointed, thick, joints 

 rounded, equal ; anterior coxfe coutiguoua, their cavities con- 

 fluent, though closed behind;* middle coxai without trochantin, 

 entirely inclosed by the sterna; hind coxse widely separated, 

 intercoxal process of the abdomen obtuse, first ventral segment 

 elongated; elytra embracing but slightly the flanks of the abdomen, 

 epipleurae narrow. Legs moderately short, tibial spurs scarcely 

 distinct, tarsi pubescent. Side pieces of metasternuni very narrow. 



The elytra are shining and coarsely punctured, the thorax 

 elongated, constricted at the middle, with a convex lateral tuber- 

 cle just in the constriction. 



This tribe contains in our fauna but one species, Davoderus 

 atriaticeps Lee, a singular insect, of small size, found under 

 bark, at the junction of the Colorado and Gila Elvers; a second 

 species has occurcd in the island of Santo Domingo (D. domini- 

 ceniiis Horn). 



Tribe XI.— STEIVOSIIIVI. 



Body slender, apterous; head constricted behind into a neck; 

 labruni covered by the epistoma; mentum large, inserted upon a 

 gular peduncle; maxillae exposed, ligula slightly prominent; eyes 

 variable in form, coarsely granulated; antennae ll-jointed; elytra 

 embracing but slightly the flanks of the abdomen ; anterior coxse 

 moderately separated; middle coxae without trochantin, inclosed 

 by the sterna; hind coxa3 moderately distant ; legs feeble, tibial 

 spurs obsolete, tarsi ciliate. Side pieces of metasternujn narrow. 



Of this tribe several species of ArsEoschizus are kiK)wn from 

 our territory; they occur in the desert regions of California and 

 Ai'izona. 



Arceoschizus is distinguished from foreign genera by the 11th 

 joint of the thick antennte being small and partly received by the 

 10th; and by the thorax being long and feebly convex. 



Sub-Family II.— ASIDIN.E. 



In this sub-family the middle coxse are contained in cavities 

 which are open externally, so as to enable the epimera of the 

 mesosternum to reach the cavities; there is also a distinct tro- 

 chantin visible in the space thus formed. To these characteristics 



* This character is known in no other Tenebrionide. 



