hat you place sexual
selection even as high as No. 4 in your summary. It was very natural
that you should give only a line to sexual selection in the summary to
the "Westminster Review," but the result at first to my mind was that
you attributed hardly anything to its power. In your penultimate
note you say "in the great mass of cases in which there is great
differentiation of colour between the sexes, I believe it is due almost
wholly to the need of protection to the female." Now, looking to the
whole animal kingdom, I can at present by no means admit this view; but
pray do not suppose that because I differ to a certain extent, I do not
thoroughly admire your several papers and your admirable generalisation
on birds' nests. With respect to this latter point, however, although,
following you, I suspect that I shall ultimately look at the whole case
from a rather different point of view.

You ask what I think about the gay-coloured females of Pieris. (443/1.
See "Westminster Review," July, 1867, page 37; also Letter 440.) I
believe I quite follow you in believing that the colours are wholly due
to mimicry; and I further believe that the male is not brilliant from
not having received through inheritance colour from the female, and from
not himself having varied; in short, that he has not been influenced by
selection.

I can make no answer with respect to the elephants. With respect to
the female reindeer, I have hitherto looked at the horns simply as the
consequence of inheritance not having been limited by sex.

Your idea about colour being concentrated in the smaller males seems
good, and I presume that you will not object to my giving it as your
suggestion.

LETTER 444. TO J. JENNER WEIR. Down, May 7th [1868].

I have now to thank you for no less than four letters! You are so kind
that I will not apologise for the trouble I cause you; but it has lately
occurred to me that you ought to publish a paper or book on the habits
of the birds which you have so carefully observed. But should you do
this, I do not think that my giving some of the facts for a special
object would much injure the novelty of your work. There is such a
multitude of points in these last letters that I hardly know what to
touch upon. Thanks about the instinct of nidification, and for your
answers on many points. I am glad to hear reports about the ferocious
female bullfinch. I hope you will have another try in colouring males.
I have now finis