f the Life History of Insects has always been of great interest
to me, as I firmly believe that we are on the verge of a great
discovery, and that the first indications are being revealed to us
through the investigation of the Biology of Insects. Some of you may,
perhaps, have watched this progress of ovipositing, as I have done,
and noticed how the female moth will hover in a peculiar way over
different plants, but does not alight until she comes to a plant near
akin to the one she is seeking. She then alights, but remains, on
tip-toe as it were, with legs outstretched and wings quivering, and
soon mounts again into the air; it is only when she alights on the
proper food plant that she shows unmistakably that she knows her quest
is ended and her eggs are laid. This particular plant has no other
attractions for her, she takes her food irrespectively from any other
flower which secretes honey, and yet, when she is ready to fulfil her
destiny, she is unerringly drawn towards that particular plant which
must be the food of her offspring. What is this wonderful sense? We
call it instinct, a name which is made to cover all other senses in
the lower animals, of which we have no cognisance ourselves. Let us
take our own senses as a guide: we find that they are all based on the
appreciation of frequencies, of greater or less rapidity, by means of
organs specially adapted to vibrate in sympathy with those pulsations,
and thus we gain knowledge of external things. Two tuning forks or two
organ pipes when vibrating close to each other, give out a pure
musical note when they are in perfect harmony, and they then have, as
it were, "rest" together; but when one is put even slightly out of
harmony, there is, in place of a pure musical note, a rise and fall of
sound in heavy throbs, strangely characteristic of "quarrelling"; in
fact, discord and "unrest."

In our sense of hearing we can only appreciate up to 40,000 vibrations
in a second as a musical sound, whereas, with Light and other
electrical phenomena, as we shall see in a later View, we can
appreciate sympathetic frequencies of not only many millions, but
indeed millions of millions in a second, and yet it is possible that,
in the sense (of insects) we are now examining of life appreciating
life, we may be in the presence of frequencies as far removed from
light as light is from sound. If, then, we may follow the analogy from
our highest senses, we seem to get a clear explanatio