FABRE'S BOOK OF INSECTS 



faint wrinkles. These two spaces are the sounding- 

 boards, or drums. The skin is finer here than elsewhere, 

 and transparent, though of a somewhat smoky tint. 



At the hinder edge of the front part are two curved, 

 parallel veins, with a cavity between them. This cavity 

 contains five or six little black wrinkles that look like 

 the rungs of a tiny ladder. They supply friction : they 

 intensify the vibration by increasing the number of 

 points touched by the bow. 



On the lower surface one of the two veins that sur- 

 round the cavity of the rungs becomes a rib cut into the 

 shape of a hook. This is the bow. It is provided with 

 about a hundred and fifty triangular teeth of exquisite 

 geometrical regularity. 



It is a fine instrument indeed. The hundred and 

 fifty teeth of the bow, biting into the rungs of the oppo- 

 site wing-case, set the four drums in motion at one and 

 the same time, the lower pair by direct friction, the upper 

 pair by the shaking of the friction-apparatus. What a 

 rush of sound I The Cricket with his four drums throws 

 his music to a distance of some hundreds of yards. 



He vies with the Cicada' in shrillness, without having 

 the latter's disagreeable harshness. And; better still: 

 this favoured creature knows how to modulate his song. 

 The wing-cases, as I said, extend over each side in a wide 

 fold. These are the dumpers which, lowered to a 

 greater or less depth, alter the intensity of the sound. 



[190] 



