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Darwin Correspondence Project

To A. R. Wallace   6 October [1868]1

Down. | Bromley. | Kent. S.E.

Oct 6th

My dear Wallace

Your letter is very valuable to me & in every way very kind. I will not inflict a long answer, but only answer your queries.2

There are breeds (viz Hamburgh) in which both sexes differ much from each other & from both sexes of G. bankiva; & both sexes are kept constant by selection.—

The comb of Spanish ♂ has been ordered to be upright & that of Spanish ♀ to lop over, & this has been effected. There are sub-breeds of Game Fowl, with ♀s very distinct & ♂s almost identical; but this apparently is result of spontaneous variation without special selection.—3

I am very glad to hear of case of ♀s Birds of Paradise.—4

I have never in the least doubted possibility of modifying female birds alone for protection; & I have long believed it for Butterflies: I have wanted only evidence for the females alone of Birds, having had their colour modified for protection.

But then I believe, that the variations by which a female bird or butterfly could get or has got protective colouring have probably from the first been variations limited in their transmission to the female sex;—& so with the variations of the male, where the male is more beautiful than the female, I believe the variations were sexually limited in their transmission to the males.5

I am delighted to hear that you have been hard at work on your M.S.6

Yours most sincerely | Ch. Darwin


The year is established by the relationship between this letter and the letter from A. R. Wallace, 4 October 1868.
See Descent 2: 196.
CD refers to the manuscript of A. R. Wallace 1869; see the letter from A. R. Wallace, 4 October 1868 and n. 1.


Descent: The descent of man, and selection in relation to sex. By Charles Darwin. 2 vols. London: John Murray. 1871.


Sexual selection, protection.

Letter details

Letter no.
Charles Robert Darwin
Alfred Russel Wallace
Sent from
Source of text
The British Library (Add MS 46434: 162–3)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 6412,” accessed on 28 November 2021,

Also published in The Correspondence of Charles Darwin, vol. 16