ANIMAL PARASITES AND MESSMATES. 



679 



d d d indicate the different cavities of the stomach that are successive- 

 ly filled when the creature feeds. These animals vary greatly in size, 

 appearance, and mode of life. Some are exceedingly minute, and of 

 delicate structure, while others have been seen that were a foot and a 

 half long. Most of them are highly voracious, taking sometimes the 

 weight of their bodies in blood at a single meal. Generally they are 

 aquatic, but a few species are met with in the brushwood and low forest 

 growth of the tropics, where they attack both man and beast when 

 opportunity offers. 



Fig. 11. Gnat {Culex pipiens), Lakva and Nymph. 



Gnats or mosquitoes are parasites that get their living in much the 

 same way as the leeches, that is, they suck the blood of other animals, 

 man being their most common victim. They differ from the leeches, 

 however, in the fact that only the females are greedy of blood, the 

 males living on the juices of plants. The females pierce the skin by 

 means of an auger with teeth at the end, and after sucking their fill 



