480 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



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 

 suck the juices of the plant through a tube-like beak. Some 

 twenty-seven distinct broods of the cicada have been distinguished, 

 seventeen of which appear at seventeen-year intervals and ten of 

 them appear at thirteen-year intervals, the former being mostly 



FIG. 404. The periodical cicada (Cicada septendecim Linn.): a, adult; 6, 

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

 females showing ovipositor at 6, and beak at a natural size. (After 

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



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," 

 filling the air with their shrill calls, which are produced by two 

 drum-like membranes on the under surface of the first abdominal 



