COLEOPTERA 



159 



Family Trogid^e 

 The Skin-beetles 



This is a small family, which is represented in this country by 

 twenty-five species. Until recently these insects were included in the 

 preceding family; they can be distinguished from scarabaeids by the fact 

 that the epimera of the mesothorax do not extend to the coxae as they do 

 in the Scarabaeidae. The members of this family are oblong, convex 

 species, in which the surface of the body and wing-covers is usually very 

 rough, and covered with a crust of dirt, which is removed with great 

 difficulty. They are small or of medium size; our most common species 

 measure from \ to \ an inch in length. The abdomen is covered by the 

 elytra; the feet are hardly fitted for digging, but the femora of the front 

 legs are greatly dilated. 



These beetles feed upon dried, decomposing animal mat- 

 ter; many species are found about the refuse of tanneries, 

 and upon the hoofs and hair of decaying animals. 



Except a few species found in the far west, all of our 

 species belong to the genus Trox (Fig. 275). Fig. 275. 



Family Lucanid^e 



The Stag-beetles 



The stag-beetles are so called on account of their large mandibles 

 which in the males of some species are branched like the antlers of a 

 stag. They and the members of the following family are distinguished 

 by the form of the club of the antennae, which is composed of flattened 

 plates; but these plates are not capable of close apposition, as in the 

 antennas of the lamellicorn beetles. In the stag-beetles the mentum is 

 not emarginate and the ligula is covered by the mentum or is at its apex. 



The adult beetles are found in or beneath 

 decaying logs and stumps. Some of them are 

 attracted at night to lights. They are said to 

 live on honey-dew and the exudations of the 

 leaves and bark of trees, for procuring which the 

 brushes of their jaws and lips seem to be de- 

 signed; but it seems probable that some species, 

 at least, feed upon decomposing wood . They lay 

 their eggs in crevices of the bark of trees, espe- 

 cially near the roots. The larvae feed upon juices 

 of wood in various stages of decay. They re- 

 semble the well-known larvae of May-beetles. 



The family is a small one ; only thirty North 

 American species are now known. 



The common stag-beetle, Lucdnus dama. — 

 The most common of our stag-beetles is this spe- 

 cies (Fig. 276). It flies by night with a loud buz- 

 zing sound, and is often attracted to lights in houses. The larva is a 

 large, whitish grub resembling the larvae of the lamellicorn beetles. It is 

 found in the trunks and roots of old, partially decayed trees, especially 



Fig. 276. 



