Prof. A. M. Mayer's Researches in Acoustics. 375 



vous substance which stretches along the slightly excavated 

 anterior side of the trachean vesicle. Upon this band is situ- 

 ated a row of transparent vesicles containing the same kind of 

 cuneiform staff-like bodies, mentioned as occurring with the 

 Acrididae. The two large trachean trunks of the fore legs open 

 by two wide infundibuliform orifices on the posterior border of 

 the prothorax ; so that here, as with the Acrididae, a part of this 

 trachean apparatus may be compared to a tuba Eustachii. 

 With the Achetidae there is on the external side of the tibia of 

 the fore legs an orifice closed by a white silvery membrane (tym- 

 panum), behind which is an auditory organ like that just de- 

 scribed. (With Acheta achatina and italica there is a tympanum 

 of the same size on the internal surface of the legs in question ; 

 but it is scarcely observable with A. sylvestris, A. domestica, and 

 A, campestris.)" 



Other naturalists have placed the auditory apparatus of diur- 

 nal Lepidoptera in their club-shaped antennae, of bees at the 

 root of their maxillae, of Melolontha in their antenual plates, of 

 Locust a viridissima in the membranes which unite the antenna 

 with the head. 



I think that Siebold assumes too much when he states that 

 the existence of a tympanic membrane is the only test of the 

 existence of an auditory apparatus. It is true that such a test 

 would apply to the non-aquatic vertebrates ; but their homolo- 

 gies do not extend to the articulates ; and besides, any physi- 

 cist can not only conceive of, but can actually construct other 

 receptors of aerial vibrations, as I will soon show by conclusive 

 experiments. Neither can I agree with him in supposing that 

 the antennae are only tactile organs ; for very often their posi- 

 tion and limited motion would exclude them from this function*; 

 and moreover it has never been proved that the antennae, which 

 differ so much in their forms in different insects, are always tac- 

 tile organs. They may be used as such in some insects ; in 

 others they may be organs of audition ; while in other insects 

 they may, as Newport and Goureau surmise, have both func- 

 tions; for even granting that Muller'slaw of the specific energy 

 of the senses extends to the insects, yet the anatomy of their 

 nervous system is not sufficiently known to prevent the supposi- 

 tion that there may be two distinct sets of nerve-fibres in the 

 antennae or in connexion with their bases; so that the antennae 

 may serve both as tactile and as auditory organs — just as the 

 hand, which receives at the same time the impression of the 



* Indeed they are often highly developed in themselves while accompa- 

 nied by palpi, which are properly placed, adequately organized, and en- 

 dowed with a range of motion suitable to an organ intended for purposes 

 of touch. 



