d in their
fertilisation, but that, having been once produced, in however great
profusion, if the insect races were all to become extinct, flowers (in
the temperate zones at all events) would soon dwindle away, and that
ultimately all floral beauty would vanish from the earth.

We cannot, therefore, deny the vast change which insects have produced
upon the earth's surface, and which has been thus forcibly and
beautifully delineated by Mr. Grant Allen: "While man has only tilled a
few level plains, a few great river valleys, a few peninsular mountain
slopes, leaving the vast mass of earth untouched by his hand, the insect
has spread himself over every land in a thousand shapes, and has made
the whole flowering creation subservient to his daily wants. His
buttercup, his dandelion, and his meadow-sweet grow thick in every
English field. His thyme clothes the hillside; his heather purples the
bleak gray moorland. High up among the alpine heights his gentian
spreads its lakes of blue; amid the snows of the Himalayas his
rhododendrons gleam with crimson light. Even the wayside pond yields him
the white crowfoot and the arrowhead, while the broad expanses of
Brazilian streams are beautified by his gorgeous water-lilies. The
insect has thus turned the whole surface of the earth into a boundless
flower-garden, which supplies him from year to year with pollen or
honey, and itself in turn gains perpetuation by the baits that it offers
for his allurement."[160]

_Concluding Remarks on Colour in Nature._

In the last four chapters I have endeavoured to give a general and
systematic, though necessarily condensed view of the part which is
played by colour in the organic world. We have seen in what infinitely
varied ways the need of concealment has led to the modification of
animal colours, whether among polar snows or sandy deserts, in tropical
forests or in the abysses of the ocean. We next find these general
adaptations giving way to more specialised types of coloration, by which
each species has become more and more harmonised with its immediate
surroundings, till we reach the most curiously minute resemblances to
natural objects in the leaf and stick insects, and those which are so
like flowers or moss or birds' droppings that they deceive the acutest
eye. We have learnt, further, that these varied forms of protective
colouring are far more numerous than has been usually suspected,
because, what appear to be very conspicuous