248 COLEOPTERA OF NORTH AMERICA. 



Mesosternum moderately long, side pieces attaining the 

 coxal cavities ; metasternum long, side pieces narrow ; epi- 

 mera visible. 



Elytra rounded at tip, covering the abdomen ; epipleurse 

 narrow ; wings perfect. 



Abdomen with five free ventral segments, the anterior two 

 sometimes more closely connected ; intercoxal process small. 



Legs moderate or long, slender ; anterior coxae large and 

 oval when separated, conical and prominent when contigu- 

 ous, sometimes with trochantin ; middle coxae with distinct 

 trochantin, sometimes nearly contiguous ; hind coxae trans- 

 verse, contiguous, or nearly so ; tibial spurs distinct ; front 

 and middle tarsi 5-jointed, hind tarsi 4-jointed ; the penul- 

 timate joint frequently emarginate; claws simple (except in 

 Nothus and Stenotrachelus). 



This family contains a moderate number of species found under 

 bark, or in fungi. The form is generally elongate, and the thorax 

 is often marked with two basal impressions ; the first joint of the 

 hind tarsi is always much elongated. 



Four tribes are separated thus : — 



Head not constricted behind ; 



Antennae with the last four joints suddenly larger. Tetkatomini. 

 Antenna? gradually thickened or filiform ', 



Claws simple, or rarely dilated at base. Melajjdkyini. 



Claws cleft to the base. Stenotkachelini. 



Head constricted behind into a small neck. Sckaptiini. 



Tribe L-TETRATOMIXI. 



This tribe is constituted of but a single genus Tetratoma, of 

 which two species are found in the Atlantic States in fungi ; they 

 are oval and convex ; the palpi are short, not much dilated ; the 

 antennae are 11-jointecl, with the last four joints equal in size, and 

 each is about three times as long as any of the preceding ones ; 

 the tibial spurs are small, and the claws are simple ; the coxa? 

 are not contiguous but separated by their respective sterna. 



Tribe II.— MELANDR1DI. 



The outer joints of the antennae are not suddenly larger, and 

 the claws, except in Nothus, are simple ; according to the posi- 

 tion of the coxos the following groups may be established, in all 

 of which the antennae are 11 -jointed : 



