nown. No part of the world presents so many brilliant birds
as South America, yet there are extensive families, containing many
hundreds of species, which are as plainly coloured as our average
temperate birds. Such are the families of the bush-shrikes and
ant-thrushes (Formicariidae), the tyrant-shrikes (Tyrannidae), the
American creepers (Dendrocolaptidae), together with a large proportion
of the wood-warblers (Mniotiltidae), the finches, the wrens, and some
other groups. In the eastern hemisphere, also, we have the
babbling-thrushes (Timaliidae), the cuckoo-shrikes (Campephagidae), the
honey-suckers (Meliphagidae), and several other smaller groups which are
certainly not coloured above the average standard of temperate birds.

Again, there are many families of birds which spread over the whole
world, temperate and tropical, and among these the tropical species
rarely present any exceptional brilliancy of colour. Such are the
thrushes, goatsuckers, hawks, plovers, and ducks; and in the last-named
group it is the temperate and arctic zones that afford the most
brilliant coloration.

The same general facts are found to prevail among insects. Although
tropical insects present some of the most gorgeous coloration in the
whole realm of nature, yet there are thousands and tens of thousands of
species which are as dull coloured as any in our cloudy land. The
extensive family of the carnivorous ground-beetles (Carabidae) attains
its greatest brilliancy in the temperate zone; while by far the larger
proportion of the great families of the longicorns and the weevils, are
of obscure colours even in the tropics. In butterflies, there is
undoubtedly a larger proportion of brilliant colour in the tropics; but
if we compare families which are almost equally developed over the
globe--as the Pieridae or whites and yellows, and the Satyridae or
ringlets--we shall find no great disproportion in colour between those
of temperate and tropical regions.

The various facts which have now briefly been noticed are sufficient to
indicate that the light and heat of the sun are not the direct causes of
the colours of animals, although they may favour the production of
colour when, as in tropical regions, the persistent high temperature
favours the development of the maximum of life. We will now consider the
next suggestion, that light reflected from surrounding coloured objects
tends to produce corresponding colours in the animal world.

This