rey or other food.

(3) In recognising members of their own species and individuals of
their own herd or troop, and in finding their own young and their own
nests.

(4) In seeking individuals of the opposite sex at the breeding season.

It is in connection with the last of these services that we come
across some of the most curious observations as to the production and
perception of odorous particles. Butterflies and moths and some other
insects have olfactory organs in the ends of the antennae and the
"palps" about the mouth. The perfumes of flowers have been developed
so as to attract insects by the sense of smell, as their colours have
been also developed to attract insects by the eye. The insects serve
the flowers by carrying the fertilizing pollen from one flower to
another, and thus promoting cross-fertilization among separate
individual plants of the same species. But probably concurrently with
this has grown up the production of perfume by the scales on the wings
of moths and butterflies--perfumes which have the most powerful
attraction for the opposite sex of the same species. Curiously enough
(for these perfumes might very well exist without being detected by
man) some of the perfumes produced by butterflies are "smellable" by
man. That of the green-veined white is described as resembling the
agreeable odour of the lemon verbena. It is produced by certain scales
on the front border of the hinder wings of the male insects, and not
at all by the females, who are, however, attracted by it, and flutter
around the sweet-smelling male. Other male butterflies produce a scent
like that of sweet briar, others like honeysuckle, others like
jasmine, and so attract the females. Other butterflies are known which
produce repulsive odours, and so protect themselves from being eaten
by birds and lizards. Again, there are moths (for instance, the
emperor moth, Saturnia), the females of which produce a perfume which
attracts the males, and is of far-reaching power. The French
entomologist, Fabre, placed one of these female moths in a box covered
with net-gauze, and left it in a room with open window, facing the
countryside. In less than an hour the room was full of male emperor
moths--more than a hundred arrived, although none had been previously
visible in the neighbourhood. They crowded over the box, and even
afterwards, when the female moth had been removed, the perfume
remained in the box, and the male moths eagerly soug