384 DR. J. B. HICKS ON THE ORGANS 
horny organ, displaying no nerve upon its surface, cannot possibly be the instrument of 
smell, for we always find in the olfactory organs a soft, moist mucous membrane fur- 
nished with numerous nerves. No such tunic is to be found in insects, at least in their 
head, or upon the surface of their bodies.” 
Robineau Desvoidy (see Ray Society vol. for 1845) considers there is still doubt on the 
the point. * He has already shown, in year 1827, that in the Crabs, as the outer antennæ 
are evidently the seat of hearing, so the inner ones are the seat of smelling ; and afterwards 
proved, in his * Recherches sur l’organisation vertébrale des Crustacés, des Arachnides, 
et des Insectes, 1828, that in the Isopodes the sense of hearing is no longer doubtful; 
in the Arachnides it is wanting, while, on the other hand, the parts pointed out as the 
mandibles are here organs of smelling, and the poison-canal in them corresponds to the 
lacrymal passage of the higher animals. In the Insects the antennæ are organs of 
smelling, and usually also of touch. They have no organs of hearing at all.” 
Kister (see Ray Society vol. for 1847, p. 306) assigns to the feelers (antennæ) of 
insects the function of smelling. In some experiments with turpentine in glass tubes 
the reporter says, * If these experiments show that the feelers betray a sensibility to the 
effect of powerful odours, it is not yet proved that these act on them directly; and so the 
evidence that the sense of smell has its seat in the feelers is defective.” 
Newport has given us a valuable paper on the use of the antennæ of insects, in the 
‘Transactions of the Entomological Society,” vol. ii. p. 229 (read in 1838, but prepared in 
1831). He examined the antennæ of Ichneumon Atropos ; he found all the joints, except 
the second, perforated all around by very minute holes. This, he says, is the structure of 
nearly all the setaceous antennæ. He observed two tracheæ passing up its whole length, 
which gave off branches at every joint, and which seemed to him—but of that he was not 
quite certain—to communicate with the holes in the antenna-wall. He also noticed å 
nerve passing throughout its length. 
From this, and from analogy with other animals, he judged it probable that the antennæ 
were not organs of smell. He instituted a series of interesting experiments which led 
to the same conclusion, and mentions that * Copris Molossus,” when in motion, ex- 
tends the plates on the end of its antenna, as if to direct the insect in its course; but 
that on the occurrence of any loud and sudden sound, it instantly closes the plates and 
retracts the antennæ, as if injured by the percussion, while the insect stops and assumes 
esi, al ht hr nn hetere in El maner. es D 
QE ind ies P ; as been observed of the antennæ, it seems probable that in s 
funetion of hearing are nid Es A — the means by which they are fitted m i 
minene : es ried in different insects, to adapt them to the perception 0 
, 3 to the habits of the species: that in some species they are eem 
; ; hey are of great, although not of vital importance 
the insect; and that the loss of both of them, more attire when as also with 
; will clearly explain in every instance the agitation, delirium, or stupor 
