PERIODICAL CICADA. 125 



at one time or another prevailed. Ttieir appearance has been recorded, 

 within the last two hundred and forty years, over the whole extent of 

 the United States, from Massachusetts to Florida, on the East ; North, 

 to Michigan and Wisconsin ; South, to the Gulf States ; West, to parts 

 of Kansas and Nebraska ; and South-west, to Louisiana and Texas. 

 And as it is now known that during all the intermediate periods these 

 insects are maturing under ground, at the depth of from one and a half 

 to six feet, we must conclude that all parts of the country where trees 

 suitable for the deposit of their eggs have grown, are, at all times, un- 

 dermined by the larvae or grubs of this insect, in different stages of de- 

 velopment. It must not be understood, however, that they are equally 

 abundant in all places. 



Sometimes two broods appear in different sections of the country in 

 the same year. These have been described as the brood of such a year. 

 But it is evident that when these insects prevail in two or more places, 

 remote from each other, they must constitute distinct broods, and 

 should be designated by their locality in connection with the year. 



NUMBER AND DEPOSITION OF EGGS. 



The eggs of the locust are laid in the twigs of all deciduous trees, 

 and sometimes, though rarely, in evergreens. They are deposited in 

 grooves, cut through the bark and into the solid wood of the twig, by 

 the finely eaw-toothed ovipositor of the female insect. In performing 

 this operation she clings to the twig, with her back downward, and 

 consequently lays her eggs in the under side of the twig. Without 

 changing her position she cuts, or rather saws, two grooves, side by 

 side, but slightly diverging at their further extremities, leaving a 

 wedge-shaped partition of wood between the two cells. When thrust 

 into the twig, the ovipositor throws up a little bundle of finely sepa- 

 rated woody fibres, free at one extremity, which secures a passage for 

 the young insects, by preventing the bark from closing over the cavity — 

 just as the surgeon prevents an opened abcess from closing too soon, by 

 placing a linen tent between the lips of the wound. The female deposits 

 about a dozen oblong whitish eggs, less than the twelfth of an inch 

 long, in each cell, placing them two and two, at an angle of about 45°, 

 tapping upon each other, and pointing towards the loose and open end 

 of the splintered fibres, directly under which they are placed. After 

 tilling the two cavities with eggs, she moves on a few steps and makes 

 two other cavities, and so on till her store of eggs is exhausted. The 

 number of eggs laid by each female is about four hundred. In those 



