chinson's _Illustrations of Clinical Surgery_, quoted by Tylor.]

[Footnote 133: For activity and pugnacity of humming-birds, see
_Tropical Nature_, pp. 130, 213.]

[Footnote 134: _Tropical Nature_, p. 209. In Chapter V of this work the
views here advocated were first set forth, and the reader is referred
there for further details.]

[Footnote 135: The Rev. O. Pickard-Cambridge, who has devoted himself to
the study of spiders, has kindly sent me the following extract from a
letter, written in 1869, in which he states his views on this
question:--

"I myself doubt that particular application of the Darwinian
theory which attributes male peculiarities of form, structure,
colour, and ornament to female appetency or predilection. There
is, it seems to me, undoubtedly something in the male
organisation of a special, and sexual nature, which, of its own
vital force, develops the remarkable male peculiarities so
commonly seen, and of no imaginable use to that sex. In as far
as these peculiarities show a great vital power, they point out
to us the finest and strongest individuals of the sex, and show
us which of them would most certainly appropriate to themselves
the best and greatest number of females, and leave behind them
the strongest and greatest number of progeny. And here would
come in, as it appears to me, the proper application of Darwin's
theory of Natural Selection; for the possessors of greatest
vital power being those most frequently produced and reproduced,
the external signs of it would go on developing in an
ever-increasing exaggeration, only to be checked where it became
really detrimental in some respect or other to the individual."

This passage, giving the independent views of a close observer--one,
moreover, who has studied the species of an extensive group of animals
both in the field and in the laboratory--very nearly accords with my own
conclusions above given; and, so far as the matured opinions of a
competent naturalist have any weight, afford them an important support.]

CHAPTER XI

THE SPECIAL COLOURS OF PLANTS: THEIR ORIGIN AND PURPOSE

The general colour relations of plants--Colours of fruits--The
meaning of nuts--Edible or attractive fruits--The colours of
flowers--Modes of securing cross-fertilisation--The
interpretation of the facts--Summary of additional facts bearing
on insect fert