144 



ELEMENTARY ENTOMC )LOGY 



lardarins), in stored meats or feathers. These are typical represent- 

 atives of a small family, Dermestidae, of oval, plump beetles, the 

 largest being about one third of an inch long. They are usually 

 grayish, brownish, or blackish, marked with colors due to minute 

 scales with which the body is covered. All of this family feed on 



a 



C 



FIG. 203. The saw-toothed grain-beetle. (Much enlarged) 

 a, adult ; /', pupa ; c, larva. (After Chittenden, United States Department of Agriculture) 



dried animal substances, and some of the smaller species are par- 

 ticularly noxious to the entomologist, as they are the worst pests 

 which he has to combat in his collection cases. 



The Saw-Horned Beetles (Serricornia) 



The tribe of saw-horned beetles includes several families of quite 

 different habits, which are very loosely related by all having serrated 

 antennae, the segments of the antennae being prolonged inward so 

 as to give the whole antenna a saw-toothed or serrate appearance. 



Click-beetles. Every boy knows the long click-beetles, or snap- 

 ping beetles (Elateridac\ which, when placed on their backs, will 

 flop up in the air with a decided click, or snap. They are flat, 

 elongate beetles, the commoner forms being about three fourths 

 of an inch long and of a dull brown color. The head is small and 

 the posterior angles of the thorax are much prolonged, giving it 



