OF THE ANTENNÆ OF INSECTS. 395 
Newport on the habits of insects, I think it may be concluded that the antennal organs 
are formed upon a plan in accordance with our present ideas of an auditory apparatus, 
and are therefore capable of hearing, and that :—1st, they consist of a cell, sac, or cavity 
filled with fluid, closed in from the air by a membrane analogous to that which closes 
the foramen ovale in the higher animals; 2nd, that this membrane is for the most part 
thin and delicate, but often projects above the surface, in either a hemispherical, conical, 
or canoe-shaped, or even hair-like form, or variously marked; 3rdly, that the antennal 
nerve gives off branches which come in contact with the inner wall of the sacs; but whether 
the nerve enters, or, as is most probable, ends in the small internally projecting papilla 
which I have shown to exist in many of these sacs, it is very difficult to say. The principal 
part of the nerve proceeds to these organs, the remaining portion passing to the muscles, 
and to the roots of the hairs, at least to those of the larger sort. The distribution of the 
nerve can be very beautifully seen in the antennæ of the Pronæus before mentioned, as 
also in Odynerus. 
Another point, which might be mentioned as rather tending by inference to the con- 
firmation of this opinion respecting the antennal organs, is that in the Shrimp and Craw- 
fish among the Crustaceans (which have a sac at the base of the antenna, commonly 
regarded as the auditory organ) there is no trace of any organs similar to those of the 
Insecta; the nerve simply supplies the hairs and muscles, 
More than a year after the reading of my former paper on this subject, one was read on 
August 30, 1858, by M. Lespés, before the Academy of Sciences, Paris, reported upon satis" 
factorily by a Committee, and subsequently published in the ‘ Annales des Sciences Na- 
turelles :’ Paris, 1858. The title of this paper was * The Auditory Apparatus of Insects." 
Both the author and the reporters seem ignorant of what I had already done on this 
Subject, as, by not being aware of the value of bleaching the integument, M. Lespés 
had very great difficulties to contend with, which would have been avoided had he 
used that process, and moreover he would have escaped a great error. He had in con- 
sequence to employ the most colourless species; and the most minute of his researches 
were upon the antenna of the Lamellicorns, Melolontha, Polyphyllus, &c., and he was 
obliged to view the organs perpendicularly only. He certainly asserts the enm of 
sacs behind the membranes, which he calls “éympanules,” and ge drawing and 
description of the ultimate branches of the antennal nerve pinsding to them. po 
states that the sac or cell (which he terms * cellule,” or “poche ") contains a ds ee 
transparent, solid body attached to the inside of the membrane; this body he " 
“otolithe.” Now, in all the numerous antennæ w ich I have observed with en à 
high powers, I have never seen this otolithe, the nearest approach to that La 2. | ? 
small chain of solid granules passing, in Tetris, from the centre of the o— = 
; Sr P a -o his directions for the observation of these 
bråne to the back of the sac. But by following his directions m de 
Structures in Melolontha, by splitting open one lamella of the antenna and viewing 
D. à 
wall from within, I have seen the very same appearance he describes, when pl 
arent otolithe is very soon resolved into its | 
With low powers. However, the app posed to be 
nature: for by using an }-inch objective and high eye-piece, the ... ee otolithe 
the otolithe is seen long before the rest of the sac; and by adjusting x s " 
