CHAPTER III 



THE BEETLE AND ITS ALLIES 



BEETLES (Coleoptera 1 ) can be distinguished from other 

 insects by the fact that the anterior pair of wings (elytra) 

 are modified to form two horny shields, covering the pos- 

 terior part of the body, while the posterior pair of wings 

 are membranous. The mouth parts are formed for biting. 2 



During development, the beetles, like the Lepidoptera 

 and Hymenoptera, undergo great changes of form. These 

 changes may be observed in the potato-beetle. In this 

 species the orange-colored eggs are deposited often in a 

 very regular manner on the under side of the potato leaf. 

 Here they develop for several days. In about a week, 

 however, the young, reddish, black-spotted larva, or " grub," 

 emerges. Like the adult beetle, it has three pairs of tho- 

 racic legs. After feeding actively for two or three weeks, 

 the larva descends into the ground, forms a naked yellow 



FIG. 41. Larva of Lachnosterna, the June bug, at roots of aster. Photo, of 

 living animals, nat. size, by V. H. L. 



s, sheath ; irrepbv, wing. 

 2 A key to some of the chief families of Coleoptera is given in the 

 Appendix to this Chapter, page 58. 



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