14 COLEOPTERA OF NORTH AMERICA. 



A very well defined family of insects, moderately numerous, 

 nearly all of a shining black color, with the elytra variously 

 sculptured with striae ; some few species of Hister and Saprinus 

 have the elytra marked with red, and a few of the latter genus 

 are metallic in color. The form of body is variable ; those of the 

 first group are oblong and flat, with prominent mandibles ; the 

 others are round, oblong, oval, globose, some depressed and some 

 convex. The species live under bark of trees, in excrements, and 

 in carcasses. When touched, the insects retract the antennae and 

 feet, appearing as if dead. 



The metasternum is marked by two distant lines diverging pos- 

 teriorly, and the first segment of the abdomen with two similar 

 ones. 



The genera in this family appear to me to have been multiplied 

 unnecessarily by later authors. I accordingly have made, when 

 necessary, two tables, one of the genera as understood in the 

 great monograph of Marseul, the other of those which appear to 

 me to be entitled to real generic distinction. 



The family may be divided into two natural sub-families, as 

 follows : — 



Antennae with the first joint very long ; elytra truncate. Histerid^b. 



Antennae with the first joint very thick ; elytra entire. Mubmidiidjh. 



Sub-Family I.— HISTERIDAE (genuini). 



The geniculate antennae, with the first joint elongated, and the 

 truncate elytra permitting the last two dorsal segments of the 

 abdomen to be visible, sufficiently distinguish this sub-family from 

 the next. 



It is divided, following the example of Lacordaire, into two 

 very natural tribes, according to the position of the head iu 

 repose : — 



Head porrected. Hololeptini. 



Head retracted, bent downwards. Histrini. 



Tribe I.— HOLOLEPTINI. 



Body very much depressed above and below ; head extended, 

 with long, prominent mandibles ; antennae inserted under the sides 

 of the front, the club not received in definite prosternal cavities ; 



