150 ORDER HOMOPTERA. 



Cicada septemdecim. 



The males are distinguished from the females by the possession of an apparatus for the 

 production of a rather sharp and rattling sound, which may be heard imto the distance of 

 a mile. The females are destitute of this apparatus, and may be known from the males by 

 the ovipositor before alluded to. The musical or sounding organs are situated on the sides 

 of the insect, just behind the wings. They consist of plaited convex membranes, of a 

 texture somewhat like thin parchment, and lodged in small cavities in the sides : these 

 membranes emit their peculiar sound by means of muscles attached to their insides, which 

 serve alternately to increase and diminish their tension with a rapidity almost inconcei- 

 vable, while other accessory members assist in augmenting the loudness of the tone thus 

 produced by the vibrating membranes. 



The Cicada septendecim is black or dusky : anterior margin of the wing-covers, and 

 larger veins or nervures orange red ; eyes, rings of the body, and legs of the same color. 

 Expansion of wings from 2^ - 3J inches. The figure near the tip of the wing-cover re- 

 sembles the letter W. 



The most interesting fact connected with the history of the seventeen-year locust, is the 

 mode in which the species deposits eggs and makes provision for its future progeny. The 

 insect, in this climate, issues from the ground about the middle of June. As soon as the 

 wings of the perfect insect are in a condition for flying, it selects a tree for the scene of its 

 future oi^erations. The sexes pair, and, soon after, the female prepares to deposit her eggs. 

 She selects the extremity of a limb for this purpose, and applies the ovipositor, which is 

 fitted both for perforating the branch, and for sawing it in such a way as to separate and 

 detach the fibres, which are afterwards made to serve as a surrounding protection to the 

 eggs. The eggs are deposited along a line in which some ten or fifteen perforations are 

 made, some of which receive two eggs apiece. Soon after her labor is accomplished, the 

 insect dies of exhaustion. The limb or twig, which has received its burthen, speedily 

 perishes, and, being nearly severed from its supporting branch, falls to the ground, bearing 

 with it the eggs ; or, if the twig be not detached, the eggs are hatched in place, and the 

 young fall or precipitate themselves to the ground. Whether hatched above or upon the 

 ground, they soon penetrate the earth, descending among the deeper roots, where they 

 attach themselves ; and there they remain, extracting the juices of the roots by means of 

 the sucker with which they are provided. 



Miss Margaretta H.Morris has the credit of having first observed the fact that the 

 larvae of the cicadidse were injurious to fruit trees, by wounding the roots with their 

 suckers, and drawing therefrom their sustenance. It would seem that in consequence of 

 these wounds, and the drainage of sap by the numerous individuals thus attached, the 

 root becomes unhealthy, and incompetent to supply the tree with its requisite amount of 

 nutriment. Under some circumstances, therefore, where a fruit-tree becomes sickly without 

 an apparent cause, a search about the roots may disclose the fact observed by Miss Morris ; 



