i88a.J 
Sense of Smell in Insects. 
273 
Thus I have repeatedly seen a Carabus monilis in my vivarium 
examine a small worm or caterpillar by moving his antennae 
over it, without actually touching the prey. Specimens of 
Vanessa urticce have made quite analogous movements on 
being regaled with moist sugar, and V. atalanta behaves in 
precisely the same way if presented with its favourite food— 
a piece of an over-ripe plum. 
On the other hand, if any substance possessing a repulsive 
odour — e.g., a fragment of carbonate of ammonia, or a lump 
of camphor, &c. — is placed in the track of an insedf, I have 
observed the antennae, if previous^ stretched forward, to be 
suddenly withdrawn and closed, just as we, on encountering 
an offensive odour, turn away our head and close or cover 
the nostrils. 
These simple facets, which anyone who is so disposed may 
with little trouble witness for himself, seem to me to carry 
very great weight. We know that insedts as a class possess 
the sense of smell in a very high degree of development. 
We know, further, that almost all animals endowed with this 
sense examine their food by smelling. Surely, then, we may 
conclude that those organs which insedls apply to, or rather 
wave over, their food, and which are thrown into a state of 
evident excitement on the approach of any odoriferous ar- 
ticle, must be the seat of the sense of smell. To suppose 
an animal examining its food by listening seems utterly 
absurd. 
Other observers have gone much farther than I have done, 
and have reached substantially the same conclusion. Thus 
Le Pere Montrousier, of New Caledonia (“ Annual Record 
of Science and Industry,” 1877), coated a weevil ( Octhor - 
rhinus cruciatus) completely over with wax, save the tips or 
clubs of the antennae. On presenting to it oil of turpentine, 
which is an abomination to most insedts, it showed strong 
marks of uneasiness, and endeavoured to escape. Another 
specimen of the same species had merely the tips of its 
antennae coated with wax, and it remained perfedtly indifferent 
to all strong-smelling substances. This pair of experiments 
must, according to the canons of indudlive reasoning, be 
accepted as conclusive, and indeed form a good experimental 
instance of the application of the “ method of difference.” 
In the first case the fumes of the turpentine are absolutely 
cut off from every part of the body save the club of the 
antennae ; yet they are perceived by the insedt, and recog- 
nised as a nuisance. In the second case the clubs alone are 
protected, and scents are no longer recognised. We are 
surely therefore warranted in the definite conclusion that the 
