90 COLEOPTERA OF NORTH AMERICA. 



Five tribes, established by Erichson, and all represented in our 

 fauna, constitute this family : — 



I. Posterior coxae contiguous ; 



Ventral segments equal in length. Synchitini. 



First ventral segment elongated. Colydhni. 



II. Posterior coxa? distant ; 



Last joint of palpi not acicular ; 



First ventral segment elongated. Bothriderini. 



Ventral segments equal in length. Pycxomerini. 



Last joint of palpi small, acicular. Ceryuxi. 



Tribe I.— SYNCHITINI. 



Most of the species of this tribe are remarkable for being 

 covered with asperities, usually bearing erect bristles; the form 

 is sometimes elongate, but frequently oval, resembling Peltis. In 

 our genera the first three tarsal joints are nearly ecpial, and the 

 tibiae have no terminal spurs, or only very small ones. 



A. Tibiae filiform, not spinous, without terminal spurs ; 



a. Antenna? not retractile under the head, 11-jointed (body elongate, 



costate) ; 

 Antenna? thick, perfoliate ; eyes very narrow, remote from the 



margin of the head. Axchomma. 



Antenna? moderate ; eyes round, lateral. Rhagodera. 



b. Antenna? received in grooves under the head ; 



Prosternum not produced behind; antenna? with 2-jointed club; 

 antennal grooves short. Coxelus. 



B. Tibia? filiform, not spinous, with small terminal spurs ; 



a. Antenna? 11-jointed, with 2-jointed club ; 



Antennal grooves wanting ; first and second joints of antenna? dis- 

 tinctly thicker ; body costate. Ditoma. 



b. Antenna? 10-jointed, club solid; 



Antennal grooves wanting. Syxchita. 



Antennal grooves distinct, subparallel. Cicoxes. 



C. Tibia? slightly thickened, with small terminal spurs, and a few small 



spines at the extremity; antenna? 11-jointed, with 3-jointed clnb; 

 (body costate) Lascoxotus. 



Tribe II.— COLYDHNI. 



Species having a cylindrical, sometimes very slender, form ; 

 found under bark. The European genus Aglenus has no eyes, 

 but in all of ours the eyes are distinct. The elytra are striate, 

 rarely ribbed. The first joint of the tarsi is elongate in all of our 



