222 COLEOPTERA OF NORTH AMERICA. 



secoud. The hind coxse are tiuiisverse, and are covered by the 

 thigbs, in repose. The flanks are continuous with the pronotuni. 

 Two tribes may be separated thus: — 



Antennae very approximate. Ptinini. 



Antunna; distant. Euckadini. 



Tribe I.— PTIMI^I. 



The antennse are very approximate at base, long and filiform ; 

 the elytra when glabrous are very much inflated, and embrace the 

 sides of the trunk very widely, leaving tlie ventral segments very 

 small and narrow. 



Our genera are : — 



Elytra inflated, smooth, glabrous. 2. 



Elytra punctured, pubescent. 3. 



2. Prothorax smooth, glabrous. Gibbium. 

 Prothorax tuberculate, pubescent. Mezium. 



3. Prothorax constricted behind. 4. 

 Prothorax narrowed, but not constricted behind; mentum triangular. 



Trigonogenius. 



4. Teeth of mentum rounded ; labrnm emarginate. Niptus. 

 Teeth of mentum acute ; labrum rounded. Ptinus. 



The first joint of the tarsi is long in Ptinus, but only ecpial to 

 the second in the other genera. 



Gibbium scotias is imported from Europe, as are some of the 

 species of Ptinus, which genus is however generally diflfiised. 

 Niptus is represented by one New Mexican, and Trigonogenius 

 by one Californian species. 



Tribe II.— ElIt'RADIlVI. 



This tribe, while evidentl}'^ related to the preceding tribe, differs 

 by having the antennse widely separated at the base ; the thorax 

 is tuberculate, the elytra are cylindrical, and do not embrace the 

 flanks. The trochanters are moderate, the tibife arc terminated 

 by a single spur; the first joint of the tarsi is long. 



Two genera constitute this tribe: — 



Tibiffi with large terminal spur: antennse of % pectinate, of 9 serrate; 



elytra with close rows of punctures. Eucrada. 



Tibije without distinct spur: antennpe slender; elytra with scattered 



granules. Hedobia. 



Each genus is represented by one species, Eucrada in the 

 Atlantic region, Hedobia in California. 



