skip to content

Darwin Correspondence Project

To Fritz Müller   2 August [1871]1

Down, | Beckenham, Kent. [Haredene, Albury, Guildford]

Augt. 2d

My dear Sir

Your last letter has interested me greatly: it is wonderfully rich in facts & original thoughts.2 First let me say that I have been much pleased by what you say about my book. It has had a very large sale, but I have been much abused for it, especially for the chapter on the moral sense; & most of my Reviewers consider the book as a poor affair.3 God knows what its merits may really be; all that I know is that I did my best. With familiarity I think naturalists will accept sexual selection to a greater extent than they now seem inclined to do.— I shd. very much like to publish your letter, but I do not see how it could be made intelligible without numerous coloured illustrations; but I will consult Mr Wallace on this head.4 I earnestly hope that you keep notes of all your letters & that some day you will publish a book “Notes of a Naturalist in S. Brazil” or some such title.5 Wallace will hardly admit the possibility of sexual selection with Lepidoptera, & no doubt it is very improbable—6 Therefore I am very glad to hear of your cases (which I will quote in next Edition) of the 2 sets of Hesperiadæ, which display their wings differently according to which surface is coloured.7 I cannot believe that such display is accidental & purposeless. Will you have the kindness to inform me, whether the yellow & white Hedychiums &c which are not visited by certain Butterflies are distinct species or mere varieties;— I suppose the former.8

No part of your letter has interested me more than that about mimicry. It is a capital fact about the males pursuing the wrong females.9 You put the difficulty of the first steps in imitation in a most striking & convincing manner. Your idea of sexual selection having aided protective imitation interests me greatly, for the same idea had occurred to me in quite different cases, viz the dullness of all animals in the Galapagos Isld, Patagonia &c. & in some other cases; but I was afraid even to hint at such an idea.— Would you object to my giving some such sentence as follows “F. Müller suspects that sexual selection may have come into play, in aid of protective imitation, in a very peculiar manner, which will appear extremely improbable to those who do not fully believe in sexual selection. It is that the appreciation of certain colours is developed in those species which frequently behold other species thus ornamented”.10 Again let me thank you cordially for your most interesting letter.—

The Abutilon turns out a new species, which Hooker is going to name, figure & describe.11 The seedlings were several weeks absolutely sterile with own flowers pollen & pollen from same plant, & fertile with pollen from any other plant. But after several weeks they became fertile in moderate degree with own flower’s pollen!12 I have seen other cases of this.— I have been suffering of late a good deal from ill-health, & have stopped all work, & am writing this away from my home.—13 On my return in a month’s time I must prepare a new Edit. of the Origin, which I will send you when published..—14

Believe me | Yours most sincerely | Ch. Darwin


The year is established by the relationship between this letter and the letter from Fritz Müller, 14 June 1871.
See letter from Fritz Müller, 14 June 1871 and n. 1. For reviews of Descent see Correspondence vol. 19, Appendix V; see also Secord ed. 2008, pp. 334–47.
CD refers to Alfred Russel Wallace; see letter to A. R. Wallace, 1 August [1871].
Müller never produced such a volume, but his collected works and letters were published in Möller ed. 1915–21.
CD and Wallace held different views on colour-based sexual dimorphism in both birds and butterflies. CD maintained that sexual selection was the primary cause while Wallace emphasised the role of protection. For earlier discussions, see Correspondence vols. 15 and 16.
See letter from Fritz Müller, 14 June 1871. In Descent 2d ed., p. 317, CD added Müller’s observation regarding the preference shown by some butterflies for flowers of a particular colour.
CD did not add the sentence to Descent 2d ed.
The new plant was described by Joseph Dalton Hooker as Abutilon darwinii (Hooker 1871; see plate on p. 515). See letter from J. D. Hooker, 26 March 1871 and nn. 1 and 2.
In Cross and self fertilisation, p. 344, CD noted that the change in Abutilon darwinii from self-sterility in its native Brazilian setting to moderate self-fertility in his hothouse took only a single generation.
The Darwins stayed at Haredene from 28 July until 25 August 1871 (see ‘Journal’ (Appendix II)).
CD worked on Origin 6th ed. between 18 June and 29 October 1871, but noted he had ‘lost two months by illness’ (see ‘Journal’ (Appendix II)).


Opinions on Descent.

Sexual selection and mimicry in Lepidoptera; sexual selection as an aid to protective imitation.

Letter details

Letter no.
Charles Robert Darwin
Johann Friedrich Theodor (Fritz) Müller
Sent from
Haredene Down letterhead
Source of text
British Library (Loan 10:34)
Physical description
6pp †

Please cite as

Darwin Correspondence Project, “Letter no. 7892,” accessed on 29 June 2017,

Also published in The Correspondence of Charles Darwin, vol. 19