ns, and carry grains of
the pollen to the next flower they visit.

We have here a very fertile line of development among the primitive
flowers. The insects begin to visit them, for their pollen or juices,
and cross-fertilise them. If this is an advantage, attractiveness to
insects will become so important a feature that natural selection will
develop it more and more. In plain English, what is meant is that those
flowers which are more attractive to insects will be the most surely
fertilised and breed most, and the prolonged application of this
principle during hundreds of thousands of years will issue in the
immense variety of our flowers. They will be enriched with little stores
of honey and nectar; not so mysterious an advantage, when we reflect on
the concentration of the juices in the neighbourhood of the seed. Then
they must "advertise" their stores, and the strong perfumes and bright
colours begin to develop, and ensure posterity to their possessors. The
shape of the corolla will be altered in hundreds of ways, to accommodate
and attract the useful visitor and shut out the mere robber. These
utilities, together with the various modifying agencies of different
environments, are generally believed to have led to the bewildering
variety and great beauty of our floral world.

It is proper to add that this view has been sharply challenged by a
number of recent writers. It is questioned if colours and scents do
attract insects; though several recent series of experiments seem to
show that bees are certainly attracted by colours. It is questioned if
cross-fertilisation has really the importance ascribed to it since the
days of Darwin. Some of these writers believe that the colours and the
peculiar shape which the petals take in some flowers (orchises, for
instance) have been evolved to deter browsing animals from eating them.
The theory is thus only a different application of natural selection;
Professor Henslow, on the other hand, stands alone in denying the
selection, and believing that the insects directly developed the scents,
honeys, colours, and shapes by mechanical irritation. The great majority
of botanists adhere to the older view, and see in the wonderful Tertiary
expansion of the flowers a manifold adaptation to the insect friends and
insect foes which then became very abundant and varied.

Resisting the temptation to glance at the marvellous adaptations
which we find to-day in our plant world--the insect-e