ON INSECT SOUNDS. 



ascertained, we are not justified in inferring from observation 

 of insect habits and actions, their possession of emotion, passion, 

 intelligence such as our own, the conception of \v])ich we derive 

 solely from experience of our own nature. For if our states of 

 consciousness elude definition, how can we even surmise what 

 passes in the brains of other animals ? If the psychical phenomena 

 of which we feel cognisant defy explanation by reference to any 

 organic processes with which we are yet acquainted, how can we 

 affirm that the thoughts and ways of insects are identical with 

 ours, because we see them do what we think we should do under 

 the same circumstances ? 



Enough has been said to show that no certain conclusions 

 respecting the psychical significance of insect voice can be 

 drawn from comparison between the voice of man and the lower 

 animals, or between the known motives of human speech and 

 the apparent motives of insect sounds. But I think we may gain 

 a better comprehension of the general subject and a new interest 

 in the particular case of insect sounds, by directing" our attention 

 to some recent researches on the physiological and physical 

 conditions which concur with certain anatomical dispositions of 

 the insect's body to the production of a true vocal function. 



The physiological definition of animal voice may be thus 

 shortly stated — sound produced by the vibration of some animal 

 membrane thrown into unrestrained movement by a current of 

 air flowing into or out of a respiratory apparatus. Under this 

 definition the insect sounds, which may be called voice, are fewer 

 in number and variety than the sounds produced by organs which 

 are not connected with respiration. In the apparatus which may 

 be called the laryngx of the insect, as in that of Vertebrata, a 

 membrane closes the tube in which it is situate, with the 

 exception of a slit in the centre ; and the free edges of this slit 

 constitute the vibrating rolid which converts a continuous stream 

 of air into an intermittent current. 



The sound is produced by vibrations of the air, not of the 



