304 Prof. A. M. Mayer’s Hxperiments on the supposed 
of the same size on the internal surface of the legs in question ; 
but it is scarcely observable in A. sylvestris, A. domestica, and 
A. campestris.)” 
Other naturalists have placed the auditory apparatus of diur- 
nal Lepidoptera in their club-shaped antenne, of bees at the 
root of their maxille, of Melolontha in their antenual plates, of 
Locusta 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 aérial vibrations, as I will soon show by conclusive 
experiments. Neither can I agree with him in supposing that 
the antenne 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 antennze, which 
differ so much in their forms in different insects, are always tac- 
tile organs. They may be used as such by some insects; in 
others they may be organs of audition ; while in other insects 
they may, as Newport and Gonreau surmise, have both func- 
tions; for even granting that Miiller’s law 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 
antennee or in connexion with their bases, so that the antenne 
may serve both as tactile and as auditory organs—yjust as the 
hand, which receives at the same time the impression of the 
character of the surface of a body and of its temperature—or like 
the tongue, which at the same time distinguishes the surface, 
the form, the temperature, and the taste of a body. Finally, I 
take objection to this statement :—‘ Newport and Goureau think 
that the antennz serve both as tactile and as auditory organs. But 
this view is inadmissible, as Erichson has already stated, except 
in the sense that the antenne, like all solid bodies, may conduct 
sonorous vibrations of the air.” Here evidently Siebold had 
not in his mind the physical relations which exist between two 
bodies which give exactly the same number of vibrations ; for it 
is well known that when one of them vibrates, the other will be 
set into vibration by the impacts sent to it through the interve- 
* 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 mtended for purposes 
of touch. 
