THE PERIODICA I, CICADA. 
SUMMARY OF THE HABITS AND CHARACTERISTICS OF THE 
CICADA. 
The periodical, or seventeen year, Cicada, often erroneously called 
the " seventeen-year locust," or merely the "locust" — a term which 
should apply only to grasshoppers 1 — is, in the curious features of its 
life history, undoubtedly the most anomalous and interesting of all the 
insects peculiar to the American Continent. This Cicada is especially 
remarkable in its adolescent period, the features of particular diver- 
gence from other insects being its long subterranean life of thirteen or 
seventeen years, during all of which time its existence is unsuspected 
and unindicated by any superficial sign, and the perfect regularity with 
which at the end of these periods every generation, though numbering 
millions of individuals, attains maturity at almost the same moment. 
To the naturalist, familiar in a general way with the peculiar habits of 
this Cicada, its regular periodic recurrences always arouses the keenest 
interest on account of the anomalous life problems presented. To those 
unfamiliar with its habits, these sudden recurrences not only startle 
but often excite the gravest fears for the safety of trees and shrubs or 
even of annual plants. 
In view of the damage often occasioned by unusual insect outbreaks, 
such fears are not unreasonable, when, without warning this Cicada sud- 
denly emerges over greater or smaller areas, filling the ground from 
which it issues with innumerable exit holes, swarming over trees and 
shrubs, and making the air vibrate with its shrill, discordant notes. 
During its short aerial life it leaves very decided marks of its presence 
in the egg slits which thickly fill all the smaller twigs and brandies, 
the killing or injury of which causes some temporary harm and a sort 
of general twig pruning not especially injurious to forest trees, but 
more so to fruit trees, and very undesirable and disastrous to young 
trees and nursery stock. (See PI. I.) 
Following briefly the history of the insect, the young ant-like larva, 
hatching from the eggs a few weeks later, escapes from the wounded 
'Mr. Say and afterwards Dr. Fitch rightly BUggesI that the name "locust," by 
which it is almost universalis designated, is doubtless from its suddenly appearing 
in such vast numbers at long intervals of time, like the migratory locust or grass- 
hopper of the Orient. 
