245 
Antennae of Insects. 
another family, Geotrupidce, Fab., which also act in the same 
manner under like circumstances. In one species of this family, 
G. Hercules , the structure of the caput antennae is different, and 
more clearly indicates its real use. It consists of three joints, 
which, upon being closed together, form an oval-shaped knob. 
The two exterior of these joints are convex outwardly and con- 
cave within, the concavities covered by a tense membrane, so that 
they somewhat resemble a kettle-drum : the middle joint is flat, 
and has a membrane extended across both its surfaces. There 
is a space beneath all the menflnxmes, which may fairly be sup- 
posed to be furnished with ramifications of nerves from the large 
one running through all the joints of the antennae from the brain. 
Here then we have a structure which almost positively indi- 
cates that the antennae are for the function of hearing, since if the 
lamellae are not for the perception of sound, they would answer 
no purpose at all, not being adapted for any other sense ; and the 
antennae of insects w^ould form a singular exception to the eco- 
nomy and fitness of nature’s works, since in no class of animals 
do we find so great a variety of structure in the same parts, and 
in none do we find a tense membrane designed for smelling, see- 
ing, or touching, but in every one in which this particular struc- 
ture is found it exists for the sense of hearing. 
These facts, connected with the previous experiments, have 
convinced me that the antennae in all insects are the auditory 
organs, whatever may be their particular structure ; and that, 
however this is varied, it is appropriated to the perception and 
transmission of sound. We have now to show the means by 
which the different structures are adapted to this purpose. From 
the observations above stated I was once much inclined to believe 
that the seat of hearing, in the antennae of butterflies and beetles, 
resides in the caput, but this cannot be the case with moths, 
ichneumons, &c. The experiments on the ichneumon by Mr. 
Marsham, as before remarked, are thought to go very far to 
prove that the antennae are the olfactory organs, since they could 
not have touched the object they were examining, being shorter 
than the ovipositor. But surely they may be equally well suited 
to the sense of hearing as to that of smelling ? Every one must 
have observed how rapid are the motions of the ichneumon, and 
how alarmed it is on the occurrence of the slightest noise. Hence, 
considering the anatomical structure of the antennae as before de- 
scribed, might not the insect be rendered sensible of the presence 
of the object of its search — the larva of Apis maxillosa — by hear- 
ing it breathe, equally well as by smelling ? That such was in- 
