INSECT MUSIC 189 



sidered to be the seat of this function. In all it 

 is little more than a cavity, over which a skin is 

 stretched like a drum-head, which thus reacts to 

 the vibration. This seems to be very often 

 " tuned," as it were, to the sounds made by the 

 particular species in which it is found. A cricket 

 w T ill at times be unaffected by any sound, however 

 loud, while at the slightest "screek" or chirp 

 of its own species, no matter how faint, it will 

 start its own little tune in all excitement. 



The songs of the cicadas are noted all over the 

 world. Darwin heard them while anchored half a 

 mile off the South American coast, and a giant 

 species of that country is said to produce a noise 

 as loud as the whistle of a locomotive. Only the 

 males sing, the females being dumb, thus giving 

 rise to the well-known Grecian couplet: 



"Happy the cicadas' lives, 

 For tliey all have voiceless wives." 



Anyone who has entered a wood where thou- 

 sands of the seventeen-year cicadas were hatch- 

 ing has never forgotten it. A threshing machine, 

 or a gigantic frog chorus, is a fair comparison, 

 and when a branch loaded with these insects is 

 shaken, the sound rises to a shrill screech or 

 scream. This noise is supposed — in fact is de- 

 finitely known — to attract the female insect, and 

 although there may be in it some tender notes 

 which we fail to distinguish, yet let us hope that 



