e among ourselves have no
sense of landscape and other beauty. How then can it exist in animals?

If there was nothing to explain but a uniform bright and showy colour,
natural selection might be sufficient to account for it. How is it,
then, that this is not the case? We have not only colour, but colour
diversified in the most elaborate and charming manner. Look at the
exquisite patterns on a butterfly's wing! look at the various delicate
arrangements of colour and pattern in flowers; or look again at the
arrangement of colour on a humming-bird--sometimes the tail, sometimes
the breast is ornamented, sometimes a splendid crest covers the head,
sometimes a jewelled gorget or ruff surrounds the throat; and these are
not uniformly coloured, but exhibit metallic and other changes of lustre
not to be imitated by the highest art. But to fully realize this, I had
best refer to a more familiar instance. Let any one examine--as an
object very easily procurable in these days--a peacock's feather. No
doubt the whole tail when expanded is very brilliant; but look closely
at the structure of a single feather; is all this arrangement needed
only to make the tail bright or conspicuous? Observe how wonderfully the
outer parts are varied; part has a metallic lustre of copper, part has
this also shot with green: then there is a delicate ring of violet with
a double yellowish border, all quite distinct from the inmost gorgeous
"eye" of green, blue, and black, and all arranged on the same feather!

Take, again, the so-called diamond beetle of Brazil; here the wing case
is black studded all over with little pits or specks, which as a whole
only give it a powdery pale-green colour; but place it in the sunlight
and look at it with a magnifying glass--each little speck is seen to be
furnished with a set of minute metallic scales showing green and red
flashes like so many diamonds. How does such a delicate ornament answer
the demands of mere conspicuousness?

But there is a stronger case than this. I before alluded to the
exquisite symmetry of the silicious and crystalline coverings of some of
the simplest forms of marine animalcules; and also I may here add the
beautiful colouring of _shells_ sometimes on the _inside_.[1] In what
possible way would this beauty serve for any purely _useful_ purpose?

[Footnote 1: See Mivart, p. 61.]

Lastly, how are we to account for the beauty of autumnal tints in woods,
or coloured _leaves_ in plants s