JULY. 215 



the head into two parts, at the same time throwing off a thin 

 membrane which covered the body. At first the wings are 

 scarcely visible ; the insect however runs about very quickly, 

 and by degrees the wings assume their full size. The leaping 

 powers of the larvse are very wonderful, the leap being per- 

 formed in the same manner as that of a salmon, by taking 

 hold of the tail with its mouth, contracting the rings of 

 the body, and then letting go the tail. If a viper had equal 

 powers in proportion to its size, it would spring nearly a 

 hundred feet. 



