TROGOSITIDAE. 87 



Prothorax not passing over the base of the elytra; side 

 pieces not distinct; coxal cavities closed in the first and 

 third sub-families, usually open behind in the second; pro- 

 sternum separating the coxae (except in Peltastica). 



Mesosternum separating the coxas, side pieces extending 

 to the coxae. 



Metasternum emarginate behind, for junction with the first 

 ventral segment ; side pieces long, narrow ; epimera not 

 visible. 



Elytra never truncate, always covering the abdomen. 



Abdomen with five free ventral segments. 



Anterior coxae transverse, separated, and not prominent 

 (except in Peltastica); middle and posterior ones transverse, 

 flat (except in Peltastica), the former separated, the latter 

 rarely contiguous. 



Legs moderate; tarsi 5-jointed, not dilated; joints 1 — 4 

 with a brush of hair beneath ; first joint very short, second 

 usually slightly elongated, last joint very long; claws simple, 

 with a broad but short bisetose onychium. 



The insects of this family were classed by Erichson with Niti- 

 dulidas, but, as very properly observed by Lacordaire, although 

 the characters are mostly the same as in that family, the different 

 plan of structure in the maxilla? and tarsi is sufficient to mark 

 them as a distinct family. 



The species live under bark ; but some Trogositoe are found in 

 houses, living on grain, by the transportation of which they have 

 been distributed over the entire globe. 



Of the four I'ecognized tribes of this family but two are found 

 in our fauna ; I consider them as indicating sub-families, aud I 

 have added a third for the anomalous genus Peltastica. 



Anterior coxa? separate, not prominent ; 



Internal lobe of the maxillse unarmed. Tkogositics. 



Internal lobe of the maxillae armed with a corneous hook. Peltida:. 

 Anterior coxae prominent, contiguous. Peltasticid.*. 



Sub-Family L— TROGOSITIDAE (genuini). 



Elongate insects, having the thorax narrowed posteriorly, and 

 somewhat distant from the elytra ; the epistome is trisinuate or 

 emarginate in front; the last three joints of the antennse form a 

 loose club, usually dentate internally; they are 11-jointed, except 



