THE CLASSIFICATION OF INSECTS 



probable that dragon-flies are the most efficient natural remedy 

 for mosquitoes. As nymphs they destroy many mosquitoes 

 in their young or "wriggler" stage, while as adults they capture 

 hosts of flying mosquitoes. 



FIG. 72. Young (nymph) of a dragon-fly, Sympetrum illotum. Showing 

 the lower lip extended. (Natural size.) 



Order Isoptera. -The order Isoptera, termites, or so-called 

 white ants (although not related to the true ants) comprises less 

 than ten species in North America, but is much better repre- 

 sented in subtropical and tropical regions. In equatorial 

 Africa and South America, for example, the termites are very 

 important insects both because of their numbers and because 

 of their habits. They have strong biting mouth-parts, and 

 they feed chiefly upon dead wood. By virtue of this habit 

 they may be of considerable benefit as scavengers, or of con- 

 siderable harm by destroying wooden poles, furniture, etc. 

 They live in large communities, usually making their nests 

 underground or in "houses" built of soil brought up labori- 

 ously grain by grain and fastened together so as to produce 

 earthen structures rising like tents or pinnacles for several 

 feet above the surface of the ground. 



The communities comprise kings and queens (males and 

 females) provided with four nearly equal, delicate, membranous 



