ON THE ANTENNJE AND HEARING OF INSECTS. 59 



THE antennae of the cockchafer (Melolontha vulgaris) are inserted 

 before the eyes, and consist of ten joints : the three first (a-b) cylin- 

 drical, the seven at the tip short, and in form of leaves (b- c). They 

 are furnished with numerous muscles, flexors (c), pretractors (h) , 

 elevators (i), abductors of the joints (k-K), and adductors of the 

 joints (/-/). They are supplied with large nerves (6-6), from the gang- 

 lionic brain (X). They are likewise supplied with considerable air 

 tubes (tracheae). 



5 



The air-tubes of the antennae ; a, a, the main branches ; b, b, the antenna! branches. 



Though it is proved by numerous observations, that insects and 

 other articulated animals (Articulata) possess the sense of hearing ; 

 yet, except in some Crustacea, the organ by which this species of 

 sensation is perceived has not been discovered ; probably because it 

 has been fancied that it ought to possess some resemblance to the 

 human ear. But it may be asked, whether it would not be possible 

 for insects to have this sensation communicated to them by means of 

 an organ altogether different from ours ? The opinion which I pro- 

 pose to give on this subject may appear rash, but I put it forth only 

 as a simple hypothesis, yet at the same time an hypothesis upon the 

 whole extremely probable. 



The antennae are generally considered to be the organs of touch, 

 properly so called ; but this conjecture is founded upon facts imper- 

 fectly investigated, if not altogether false. I have made numerous 

 researches on this subject, and I have never been able to satisfy myself 

 that insects examine objects by feeling them with their antennae. On 

 the contrary, I have rarely observed these animals touch any thing 

 with these organs, and when this did happen, it appeared to be only 

 by accident, and not at all from design* Many insects, besides, have 

 their antennae so short, that they would be obliged to stand erect flpon 

 their heads in order to come at the bodies which they might thus wish 

 to explore, and for this their feet are certainly much better adapted. 



Since almost all articulated animals possessing a solid skin (jpeau) 

 have antennce, which are furnished with nerves of an extraordinary 

 thickness in proportion to their own size, there cannot remain a doubt 

 that they are organs of some sense, and that too a very acute one. 



