82 COLEOPTEllA OF NORTH AMERICA. 



angulate externally and narrowly closed behind. Middle coxae 

 always separated, but in some narrowly. Eosterior coxae con- 

 tiguous. Abdomen witii six segments subequal in length or with 

 the first a little longer, the sixth usually very short. Antennae 

 variable in the number of the joints, either ten or eleven, club 

 variable of 3-4 or five joints ; arising under a slight frontal mar- 

 gin in all of the genera. Tarsi variable. 



Tins tribe consists of small species, which live either in decom- 

 posing fungi or under the bark of dead trees. 



A. — Head without antennal grooves beneath. 

 Hind tarsi .'i-jointed. Mesosternum not carinate. 



Antennal club 3-jointed. Triarthrou. 



Antennal club 5-jointed. Hydnobius. 



Hind tarsi with a less number than five joints. Mesosternum carinate. 

 Tarsi with joints 5 — 5 — 4 in both sexes. 



Antennal club 4-jointed. Anogdus. 



Antennal club 5-jointed. Anisotoma. 



Tarsi 5 — 4 — 4 in both sexes. 



Antennal club elongate, loose, 3-jointed. Colenis. 



B. — Head with distinctly limited antennal grooves. 



Antennal club 5-jointed, elongate ; tarsi dissimilar in the sexes. Liodes. 

 Antennal club 4-jointed ; tarsi similar in the sexes. 



Antennae apparently 10-jointed. Cyrtusa. 



Antennal club 3-jointed. Tarsi dissimilar in the sexes. 



Antennae 10-jointed. Isoplastus. 



Antennae 11-jointed. 



Hind tarsi 4-jointed in both sexes, the mesosterniim not carinate 



between the coxae. . Agathidium. 



Hind tarsi 3-jointed, mesosternum strongly carinate. Aglyptus. 



Tribe VI.— CLAMBIIVI. 



Body oval, capable of being more or less contracted into a ball. 

 Anterior coxce conical, moderately prominent, contiguous, with 

 Tnoderate trochantin, the cavities angulate externally and closed 

 behind. Middle coxae separated by the mesosternum in Empelui^ 

 and by a fine carina in the other genera. Posterior coxae con- 

 tiguous with plates covering the thighs, partially in Empelu^ or 

 completely in Clambim and Calijplomerun. Antenna of eleven, 

 ten, or nine joints variably inserted, either contiguously to the 

 eyes (in Clambus) or distant, but not under a frontal margin. 

 Tarsi four-jointed, tibiae without spurs. 



