358 GOUREAU ON THE 



escapes an attentive search, wliilst amongst the grasshoppers 

 and crickets, a sliglit examination is sufficient to find the instru- 

 ment (of music), even when its use is unknown. It is not, 

 therefore^ surprising, that there should be more uncertainty 

 about the organ of song in tiiese insects, than in the crickets 

 and grasshoppers. 



All the locusts are not equally good musicians, nor have 

 their musical instruments the same degree of perfection. Some 

 are found on the stalks of plants or on the leaves of shrubs, 

 where they make the air resound with their continual singing. 

 Their song is sharp and monotonous, composed of innumerable 

 couplets of eight or ten seconds in length, separated by an 

 interval of two or three seconds. When they have sung in this 

 way for some time, if they do not see a female, they fly off and 

 settle on another stalk, where they recommence their stridula- 

 tion. If they see the female approach, or become by instinct 

 aware of her presence, they redouble their ardour while she is 

 at a distance, but when she comes near, they lower their tone, 

 and the stridulation assumes a soft and tender character. 

 Other kinds, the voice of which is less loud, are almost always 

 met with on the grdund, where they walk with facility, and 

 even run with a tolerable degree of rapidity. They remain 

 there silent till the moment they perceive a female, when they 

 run towards her, but stop at a short distance, and make a faint 

 stridulatory noise, in order to hear which it is necessary to 

 listen attentively. 



When a cricket sings, he stands on his four anterior legs, 

 and doubles the hind legs up against the thighs, where they 

 are received into appropriate grooves, then he rubs the thighs 

 rapidly against the elytra. The best musicians execute this 

 movement with rapidity, and for some time together ; those 

 who have less taste for singing, pass the thighs two or three 

 times only against the elytra. Amongst these latter, it is not 

 unusual to observe some who put their thighs, one after the 

 other, in motion, or who move them together without produc- 

 ing any sound. From this circumstance it may be conjectured, 

 that there are sounds imperceptible to our ears which make an 

 impression on more delicate organs, as there is a light invisible 

 to us which acts on eyes more sensitive than those which we 

 possess. There are, doubtless, diurnal, crepuscular, and noc- 

 turnal insects, which proves the existence of eyes capable of 



