56 SUPPLEMENT ON 



manifested in the perfect insect, with this difference, that the 

 ganglia are remote from, or approach each other according 

 as the larva, being short, produces an elongated insect, or 

 vice versa. The antlion is an example of the first, and the 

 scarabeus of the second. 



There cannot be the least doubt that the parts of which 

 we now treat are the instruments by which the insect per- 

 ceives its sensations, and that these nervous threads transmit 

 into the organs the sensibility with which they are endowed, 

 thus connecting together all the parts of the body. Positive 

 experiment would have demonstrated this, even if it were not 

 evident from analogy. We shall now proceed to examine 

 the modes in which insects perceive their sensations, omitting 

 all mention of the eye, which has been already sufficiently 

 treated of. 



All naturalists are persuaded that insects are possessed of 

 the faculty of perceiving sounds, or vibrations of the air, 

 since many insects produce them under such circumstances 

 of their lives, as render it important that they should reci- 

 procally manifest their existence to each other. The various 

 sounds produced by insects, and which it is quite unneces- 

 sary to enumerate here, were undoubtedly destined to be 

 perceived by some specific organ. That insects hear, even 

 in the larva state, is proved by some observations of Bonnet, 

 though that naturalist denied them this faculty. The sound 

 of his voice, and the ringing of a small bell, evidently affected 

 some caterpillars, which Bonnet referred to their sense of 

 touch. Flies will move their legs at distinct sounds, and the 

 social insects evidently intercommunicate by peculiar noises. 

 Some orthoptera and hemiptera, whose males are vocal, afford 

 the best proof of the existence of this sense. The females 

 have been observed to attend to their call, and a tolerably 

 loud sound will stop their chirping. But the seat of this 

 sense yet remains undiscovered ; " perhaps," says M. Dumeril, 



