236 COLEOPTERA OP NORTH AMERICA. 



to be deeply emarginated or even divided ; the antennse are 

 gradually thickened externally, not differing according to sex. 



The species live on fungi, which grow upon trees or under 

 their bark. Our genera are two, both having the sides of the 

 thorax broadly flattened. 



Antennae 10-jointed ; eyes not entirely divided. Phellidhts. 



Antennse 11-jointed ; eyes completely divided. Boletophagus. 



No species of this group is yet known from the Pacific district. 

 The type and only species of Phellidius is Boletophagus cornutus 

 Fabr.; the genus is indicated but not named by Lacorclaire, 

 Gen. Col. v, 295. Of Boletophagus two species are known in 

 our fauna. 



Group II.— Rhipidandri. 



Of this group but a single species is known to me, Bhipidan- 

 drus Jlabellicornis Lee. (Xyletinus flabellicornis Sturm), a small, 

 oval, opaque black insect, with finely ribbed elytra and yellow 

 legs and antennae ; it is found throughout the Middle and Western 

 States. 



The front is not dilated either in front or at the sides, and the 

 base of the mandibles is exposed ; the eyes are rounded, scarcely 

 emarginate. The antennae are 11-jointed; gradually thickened 

 externally in the female with the middle portion sub-serrate ; 

 strongly pectinate in the male, the joints 5-11 being much pro- 

 longed anteriorly, the 5th, however, being less prolonged than 

 the others. 



Tribe XII.— DIAPEREVI. 



Body oval or rounded, winged ; head received in the thorax as 

 far as the eyes, which are transverse and coarsely granulated ; 

 front somewhat dilated at the sides, covering the base of the man- 

 dibles ; epistoma truncate, separated from the labrum by a short 

 coriaceous clypeus ; antennae more or less thickened externally, 

 perfoliate ; mentum small ; gular peduncle distinct ; elytra with 

 narrow epipleurae. Anterior coxae transverse ; middle coxas with 

 distinct trochantin ; legs slender ; tibial spurs small ; tarsi pubes- 

 cent beneath. 



Two groups are thus distinguished : — 

 Eyes entire. Pentaphyixi. 



Eyes emarginated by tbe sides of the front. Diapeees. 



