The Life of the Grasshopper 



either do not tell us or else tell us very 

 vaguely and inaccurately, talking of a friction 

 of the wing-cases, mutual rubbing of the 

 nervures ; and that is all. 



I should like a more lucid explanation, for 

 a Grasshopper's musical-box, I feel certain 

 in advance, must have an exact mechanism 

 of its own. Let us therefore look into the 

 matter, even though we have to repeat ob- 

 servations already perhaps made by others, 

 but unknown to a recluse like myself, whose 

 whole library consists of a few old odd 

 volumes. 



The Decriais' wing-cases widen at the 

 base and form on the insect's back a flat 

 sunken surface shaped like an elongated 

 triangle. This is the sounding-board. Here 

 the left wing-case folds over the right and, 

 when at rest, completely covers the latter's 

 musical apparatus. The most distinct and, 

 from time immemorial, the best-known part 

 of it is the mirror, thus called because of 

 the shininess of its thin oval membrane, set 

 in the frame of a nervure. It is very like 

 the skin of a drum, of an exquisitely delicate 

 tympanum, with this difference, that it sounds 

 without being tapped. Nothing touches the 

 mirror when the Decticus sings. Its vibra- 



260 



