SOME INSECTS INJURIOUS TO ORCHARD FRUITS 549 



doubtless associated its vast noisy swarms with the devastating 

 invasions of the Migratory Locust of the East. Hence the popular 

 name locust, which has been used so long that it is doubtful if it 

 will ever be discarded for the proper name Periodical Cicada." 

 They are quite different from the true locusts, or grasshoppers, 

 however, for the latter have biting mouth-parts while the cicadas 

 are true bugs and suck the juices of the plant through a tube-like 

 beak. Some twenty-two distinct broods of the cicada have been 

 distinguished, thirteen of which appear at seventeen-year intervals 

 and seven of them appear at thirteen-year intervals, the former 



FIG. 400. The periodical cicada (Cicada septendecim Linn.): a, adult; b, 

 young nymph enlarged; c, cast skin of full grown nymph; d, adult 

 females showing ovipositor at b, and beak at a natural size. (After 

 Marlatt and Riley, U. S. Dept. Agr.) 



being mostly in the North and the latter mostly in the South. 

 Some one or more of these broods appears in every State east of 

 the Rockies except Maine, New Hampshire and Vermont. Every 

 year there is a brood emerging in some part of the country, and 

 the different broods have been carefully mapped so that their 

 emergence may be anticipated. 



Life History. The adults appear in immense swarms in late 

 May or early June. " About four or five days after their first 

 appearance," says Dr. Hopkins, " the males begin to sing " 



