256 



ACROXOMY 



FIG. 185. Ladybng 



Showing larvae and mature 

 insect 



the bulk of their diet, seeming to prefer them to seeds. Even 

 those listed as true seed eaters do not feed to any great extent 

 upon the seeds of cultivated plants, and 

 usually feed their young upon insects. In- 

 sects also have their contagious diseases, 

 and may be exterminated by spreading 

 the infection among them. Last, but by 

 no means least, are the insects that prey 

 upon others. The dragonfly, often called 

 the mosquito hawk, feeds almost exclu- 

 sively upon mosquitoes ; the tiger beetle 

 attacks and 

 kills many 

 kinds of in- 

 sects ; the ant lion preys upon 

 ants ; ground beetles eat the eggs 

 of other species ; the spider cap- 

 tures flies, grasshoppers, crickets, 

 and the like ; and certain wasps 

 stock the larder for their young 

 with captured flies. The ladybird, 

 or ladybuy, lives almost entirely 

 upon aphids and scale insects, 

 both in the larval and the mature 

 state, and is one of the most effec- 

 tive aids we have in keeping these 

 pests in check. Most remarkable 

 of all, however, are the ichneumon 

 flies which deposit their eggs in 

 the larvae of other insects. Some 

 are equipped with long oviposi- 

 tors, by means of which they are 



FIG. 186. One of the larger ich- 

 neumon flies. (About natural size) 



able to reach the larvse of boring species, deep in the trunks 

 of trees. When the eggs hatch, the young worms live upon 



