ORTHOPTERA. 133 



ducing sounds, have not the cymbals and tabors of the crickets 

 and grasshoppers ; their instruments may rather be likened to 

 violins, their hind-legs being the bows, and the projecting veins of 

 their wing-covers the strings. But besides these, they have on 

 each side of the body, in the first segment of the abdomen, just 

 above and a little behind the thighs, a deep cavity closed by a 

 thin piece of skin stretched tightly across it. These probably act 

 in some measure to increase the reverberation of the sound, like 

 the cavity of a violin. When a locust begins to play, he bends 

 the shank of one hind-leg beneath the thigh, where it is lodged in 

 a furrow designed to receive it, and then draws the leg briskly up 

 and down several times against the projecting lateral edge and 

 veins of the wing-cover. He does not play both fiddles together, 

 but alternately, for a little time, first upon one, and then on 

 the other, standing meanwhile upon the four anterior legs and 

 the hind-leg which is not otherwise employed. It is stated that, 

 in Spain, people of fashion keep these insects, which they call 

 grillo, in cages, for the sake of their music. Locusts leap much 

 better than grasshoppers, for the thighs of their hind legs, though 

 shorter, are much thicker, and consequently more muscular 

 within. The back part of the shanks of these legs, from a little 

 below the knee to the end, is armed with strong sharp spines, 

 arranged in two rows. These may serve as means of defence, 

 but the lower ones also help to fix the legs firmly against the 

 ground when the insect is going to leap. The power of flight in 

 locusts is, in general, much greater than that of grasshoppers ; for 

 the wing-covers, being narrow, do not, like the much wider ones 

 of grasshoppers, so much impede their passage through the air ; 

 while their wings, which are ample, except in a few species, and 

 when expanded together form half of a circle, have very strong 

 joints, and are moved by very powerful muscles within the chest. 

 From the shoulders of the wings several stout ribs or veins pass 

 towards the hinder margin, spreading apart, when the wings are 

 opened, like the sticks of a fan, and are connected and strength- 

 ened by little crossing veins, which form a kind of net-work. The 

 same structure exists in the wings of grasshoppers, but in them 

 the longitudinal ribs are not so strong, and the network is much 

 more delicate. Hence the flight of grasshoppers is short and un- 



