72 POWER OF VARYING SOUND. 



continually and contentedly on A', but if it is excited 

 or angry it produces a very different note. Thus, 

 then, the sounds of insects do not merely serve to bring 

 the sexes together ; they are not merely " love-songs," 

 but also probably serve, like any true language, to 

 express the feelings. 



Landois also describes the muscles by means of 

 which the form of the organ, the tension of the drum, 

 etc., is altered, and the tone thus, no doubt voluntarily, 

 affected.* We can, indeed, only in few cases distinguish 

 the differences thus produced; but as even we, far 

 removed as we are in organization, habits, and senti- 

 ments, from a fly or a bee, can yet feel the difference 

 between a contented hum and an angry buzz, it is highly 

 improbable that their power of expressing their feelings 

 should stop there. One can scarcely doubt but that 

 they have thus the means of conveying other sentiments 

 and ideas to one another. 



Butterflies and moths do not habitually produce any 

 sound in flight. The texture of their wings is com- 

 paratively soft, and they are generally moved slowly. 

 Still, they are not altogether silent. 



The death's-head moth (Sphinx atropos) emits a 

 mournful cry, first noticed by Reaumur. This moth, 

 he says, " dans le temps qu'il marche, a un cri qui a 

 paru funebre ; au moins est-il le cri d'une bonne ame 

 de papillon, s'il gemit des malheurs qu'il annonce. 



*' Le cri de notre paj)illon est asses fort et aigu ; il a 

 quelque ressemblance avec celui des souris, mais il est 

 plus plaintif ; il a quelque chose de plus lamentable. 

 C'est surtout lorsque le papillon marche, ou qu'il se 



* " Die Ton and Stinim Apparate der Insekten," Zeit. fur Wis8. 

 Zool, 3866, 



