224 COLEOPTERA OF NORTH AMERICA. 



Front coxae seijarated by prosternnm. 2. 



Front coxae conical, contiguous, prominent. Ernobius. 



2. Prosternum moderate ; tarsi narrow. Ozognathus, 



Presternum very short ; tarsi broad. Xestobium. 



These genera are represented on both sides of the continent. 

 Ozognathus cornutus, bred from oak galls in California, is re- 

 markable by the mandibles Of the % being provided at base with 

 a long, slender, curved horn, which, at tip, meets its fellow of the 

 opposite side. 



Sub-Group 2. — A n o b i a . 



The body is usually elongate in form; the head is capable of 

 being strongly deflexed, and rests in repose in the excavated 

 under surface of the prothorax : the antenna? usually received into 

 a more or less distinct excavation between the front and middle 

 coxiE, which is sometimes prolonged into the metasternum. The 

 mandibles do not reach the metasternum, and the head is never 

 excavated beneath for the reception of the antennte. The antenna? 

 usually have the last three joints enlarged, and the stem not ser- 

 rate, though these characters vary much. The anterior opening 

 of the prothorax is circular: the epipleurog are foveate for the 

 reception of the knees in Petalium and Theca, and the hind legs 

 are received in ventral excavations in Theca and Eupactus. 



The genera arc numerous and may be tabulated as follows: — 



First ventral segment not excavated. 2. 



First ventral segment excavated for reception of liind^legs. . 12. 



2. Metasternum not excavated in front. 3. 

 Metasternum deeply excavated in front. 10. 

 Metasternum produced in front into a large lobe. 11. 



3. Antennae not received between the coxae, but resting upon them. 4. 

 Antennae received between the front coxae. 5. 



4. Front coxae contiguous ; antennae 9- or 10-jointed. Oligomerus. 

 Front coxae nearly contiguous ; antennae 11-jointed. Sitodrepa. 



5. Antennae not pectinate. (j. 

 Antennae pectinate. Ctenobium. 



6. Thighs not clavate. 7. 

 Thighs strongly clavate ; tarsi dilated. Ptinodes. 



7. Tarsi slender. S. 

 Tarsi dilated. 9. 



8. Prothorax margined ; ventral segments separate. Hadrobregmus. 

 Prothorax not margined ; first and second ventral segments connate. 



GastralluB. 



9. Claws broadly toothed. Trlchodesma. 

 Claws not toothed. Nicobium. 



