SNAPPING-BEETLES. 45 



FAMILY ELATERIDAE. 



(Snapping, Clicking, or Spring-beetles). 



Notwithstanding" the large number of beetles that form this 

 family, they are nearly all readily recognized in all of their stages, 

 and every boy knows the acrobatic performances of the adult 

 snapping-beetles. If touched ever so lightly the beetle drops to 

 the ground, usually landing upon its back; after remaining per- 

 fectly quiet for a time, as if dead, we hear a sudden click, the 

 beetle pops into the air, and falling upon its short legs, runs 

 away. When we study the under side of the beetle to discover 

 the means which enable it to act in this peculiar fashion, we find 

 that the pro-thorax is loosely jointed to the rest of the body, and 

 that on its under side there is a curved horn 'which fits into a 

 cavity of the meso-thorax (Fig. 53). When such a beetle is laid 



Fig. 53. — Elater ready to snap. After Smith. 



on its back it bends in such a way as to bring the tip of the curved 

 horn to the edge of the cavity, and by a sudden release of mus- 

 cular tension, this tip slips and the insect is thrown into the air. 



Most of our snapping-beetles are small, or of medium size, 

 but a few are quite large, sometimes reaching two inches in 

 length. As a general rule they are of a uniform brownish color; 

 some are black or grayish, and still others are gayly colored, even 

 metallic. The very elongated body tapers more or less towards 

 each end, and is sometimes flattened . The feelers are moderately 

 long, more or less serrated, very much so in the males of some 

 rather uncommon species. The outer angles of the very wide 

 pro-thorax are usually prolonged into points, which curve around 

 the edge of the wing-covers. 



