90 GOUREAU ON THE 



against each other, or is produced by any other mechanical 

 cause, it is not a true voice, and shoukl be designated by a 

 new word, in order to distinguish, by different appellations, 

 things which are in themselves distinct, and to prevent the 

 possibility of confounding articulate sounds with those that 

 are entirely mechanical. It is my intention, in this memoir, 

 to show that insects have no true voice, and in lieu thereof are 

 provided with musical instruments, by the use of which its 

 place is sufficiently supplied. Instead of calling them song- 

 insects, it will be better, after the example of the illustrious 

 Latreille, to designate them as musicians. Stridulation appears 

 to me a very suitable word by which to designate the sounds 

 they produce. I shall employ it in this acceptation, but do 

 not intend to discard entirely the terms toice and song, which 

 are in general use, as these will frequently enable me to avoid 

 tautology. 



There have been many hypotheses invented to explain the 

 production of the song of insects. Some authors have affirmed 

 that it was generally caused by the friction of the elytra against 

 each other ; and this is in many instances correct ; but the 

 hypothesis was incomplete, inasmuch as it was not accompanied 

 by an intimation of the way in which this friction produced 

 stridulation, or a description of the musical instruments of 

 such as were the subjects of observation. Others have attri- 

 buted these sounds to the action of air included between the 

 elytra, which, escaping when the insect rubs them against each 

 other, rushes against the nervures by which they are divided 

 into compartments, and causes them to vibrate and produce a 

 sound ; but this is not the fact. Other entomologists have 

 thought that the noise results from certain specific internal '■. 

 organs. The structure of the Cicadcp. seems to have furnished 

 the origin of this hypothesis, which does not apply to all the 

 other sound-producing insects. Lastly, a learned foreign ento- 

 mologist'' has recently conjectured that the vocal organ of the 

 locusts resides in the sub-alary cavities which these insects 

 possess, and that the song of the crickets and grasshoppers is 

 produced by the rapid emission of air through the posterior 

 stigmata of the prothorax, which passes along the elytra, and 

 causes a vibration of the sonorous membrane. But this idea 



'' Vide the Revue Entomologiqiic, Vol. I. p. 161. 



