262 



NATURAL HISTOKT. 



lice. In the first three of these families, the insect in its 

 larva and pupa states inhabits the water, respiring like a 

 lish, having peculiar organs for this purpose at the sides 

 of the abdomen or at its end, while in the form of its 

 ^h»4yit is quite like the insect in its perfect state. 

 J 450?"^ the Dragon-flies, the most conspicuous and 

 best-known family, there are about two hundred ascer- 

 tained species. These are the Swallows of the Insect 



