BYRRHIDAE. 159 



Elytra covering the abdomen; epipleurffi obsolete behind. 



Abdomen with five ventral segments, the anterior three 

 subconnate in some genera. 



Anterior coxee transverse, not prominent, with large tro- 

 chantin; middle coxte flat, transverse, oval, with large tro- 

 chantin; posterior cox^e subcoutiguous, extending to the 

 margin of the body, transverse, dilated into a plate partly 

 protecting the hind thighs. 



Legs short, stout, retractile; tibiae dilated, usually sulcate 

 externally for the reception of the tarsi; tibial spurs distinct; 

 tarsi short, 5-jointed, the third joint frequently prolonged 

 into a membranous lobe beneath, last joint nearly as long as 

 the others united; claws simple. 



This family comprises three sub-families, as follows: — 



AiitimnK inserted at the side of tlie head; 



Head prominent, mentnrn large. Nosodendrin^e. 



Head retracted, mentum small. Byrrhin.^. 



Antennae inserted on the front ; head retracted. Chelonariin^. 



Sub-Family I._NOSODENDRIN^. 



But a single genus, Nosodendron, constitutes this sub-family. 

 It is represented in Europe by one species, and in the Atlantic 

 and Pacific regions, respectively, also by single species. It is 

 sufficiently distinguished by the large, elongate, semi-elliptical 

 mentum, entirely closing the mouth below, leaving only a very 

 narrow portion of the maxillse to fill the fissure on each side; the 

 head is advanced; the antennae Il-jointed, situated under the 

 side of the head; the labrum is indistinct; the tarsi not lobed. 



They are less than one-fourth of an inch long, oval, convex, 

 black, densely punctured, and are found under bark of trees. 



Sub-Family II._BYRRHIX^. 



In this sub-family the head is retracted; the mentum small, 

 quadrate; the base of the maxillae largely exposed; the labrum 

 distinct; the antennae inserted under the sides of the head. 



We would arrange these genera in three tribes: — 



Epistoma short, coriaceous ; antennae ll-jointed. AMPnirvRTiNi. 



Epistoma not distinct; antennae clavate, ll-jointed. 15ykriiini. 



Epistoma corneous, separated by a fine suture; antennte 10-jointed. 



LlMNlCHlNI. 



