LEPIDOPTRROUS INSECTS. 83 
numerable number of spiracles along each side of 
their bodies, where then can this organ be situated ? 
The theory of smell in the higher animals is, that it 
is felt by a current of air which is impregnated with 
odoriferous particles passing through a moistened 
channel. This was first most ably described by 
Schneider, nearly two centuries ago.* Reasoning 
from analogy, we would say that insects enjoy this 
sense by the same process. Hence Baster, Cuvier, 
Dumeril, and Lehmann, are of opinion, that insects 
perceive odours by means of their breathing holes. 
Blainville says the antenne are the organs of 
smell. He is of opinion that the modification of the 
skin with which they are invested, is in general 
olfactory only in a small degree ; this power appear- 
ing to be more acute in the thickest parts of the 
organs, where it is more soft and tender. A difficulty 
to the establishment of this theory is, that spiders 
have no antenne, consequently do not possess this 
sense, if his doctrine were true. Latreille entertains 
the same opinion ; “ for,” says he, “the exercise of 
smell consists only of the action of the air impreg- 
nated with odoriferous particles on the nervous, or 
olfactory membrane, which transmits the sensation. 
If insects are really endowed with an organ furnished 
with similar nerves, and with which air, charged 
with odoriferous particles, comes in contact, such an 
* De Sensu ac Organo Odoratus. Witteb, 1655, 
