THE CHAMELEON FLY. 435 



and leaps to a considerable distance when disturbed. 

 To do this it erects itself on its tail, and, bending 

 its head into a circle, fixes two black claws at the 

 end of the tail into two cavities formed for their 

 reception at the back of the head. It then exerts 

 its muscular powers, and, in suddenly extending its 

 body, throws itself, for its size, to a vast distance* 

 One of these, not a fourth of an inch long, has been 

 known to leap thus out of a box six inches deep, or 

 to twenty-four times its own length. 



The rottenness of cheese is in a great measure oc- 

 casioned by these little maggots ; for they crumble 

 the substance of it into small particles;, and the 

 smallest tainted spot immediately spreads when any 

 of them get upon it. 



When they are about to change into chrysalids, 

 they desert the cheese, and in three or four days 

 afterward grow stiff and lifeless. The fly bursts 

 through an opening in the skin just at the head, 

 which there divides into two parts. At its first ap- 

 pearance the wings are not fully formed, but it is able 

 to run about with great activity : the wings expand 

 by degrees, and in the course of a quarter of an hour 

 they are perfected* 



In the ovary of a single female no fewer than 

 two hundred and fifty-six eggs have been found. 



THE CHAMELEON FLY*. 



This is one of our most common two-winged in- 



* Musca Chamaeleon. Lim- 



F f 2 



