12 



cust instinctively avoids, though they are sometimes seen there. 

 This hypothesis supposes that such places are unfit for the purpo- 

 ses of propagation, and is true in part, but requires some explana- 

 tion. Instinct always directs it to such places as are best adapted 

 to its economy. We find it on the mountain tops, and in the plains, 

 where there is a soil to rear trees and shrubs, without which there 

 could be no place to deposite their eggs. They are equally re- 

 pelled by a rocky and a sandy soil, in neither of which they could 

 find subsistence, or construct their habitations. They do not bur- 

 row in a soil usually saturated with water, on the shores of water 

 courses, nor the margins of meadows or marshes ; though we have 

 them down the declivities of hills, till they are repelled by a cold, 

 damp soil. 



As we have given some imperfect description of the note of the 

 locust, \ve must attempt to describe the instruments by which it is 

 produced a task the more difficult because we cannot judge very 

 accurately by comparing them with any thing. There is some- 

 thing in vocal music, the result of living animal matter, that art 

 cannot aspire to, nor scarcely imitate. 



If we view the body externally, we perceive, under the shoulders 

 of the wings, a small, delicate membrane, nearly triangular, and con- 

 vex, with fine, long ridges, or ribs running over it. It resembles a 

 small shell, and is stretched over a cavity, in the chest, like the head 

 of a drum, each lower angle being intimately connected with a fasci- 

 culus of muscular fibres. There are two scales, one on each side of 

 the thorax, firmly attached above and below. By bending the body 

 backwards, they are elevated, and expose two larger cavities, covered 

 by an exquisitely fine, silk-like membrane. Those cavities are con- 

 nected with those under the musical membranes, and are the reservoirs 

 of air, with which they are filled. The upper ends of fasciculi of 

 muscular fibres, are tied doicn to the inner centre of the breast bone, 

 and the lower ends pass through the sides of the posterior cavity of 

 the chest, attached by a ligament, to the inferior angle of the musical 

 membrane, forming together, a triangle, and span the chest like the 

 rafters oj a house. 



