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Darwin Correspondence Project

To Henry Doubleday   15 April [1868]1

April 15th

My dear Sir

I fear that you will think me the most unreasonable of men; & if your occupation or state of health do not permit you to answer & I know you would do so if you could, will you return the list in the enclosed envelope, without a word, & I shall understand how the case is.—2 Considering the list, I have become curious on two points which are of importance to me, & which I have endeavoured to ascertain for myself, but have failed from so many synonyms being used & from so many of the insects not being British. The first point whether the 12 names of moths, marked with blue [TICK] in which the ♀ apparently are the most numerous, are as brightly coloured, (ie colour with red, dark yellow, purple or any bright colour) as the others on the list, in which the males apparently the most numerous.—3

Secondly if you were to suppose that you separated the latter (ie the 130 with males the most numerous) & compared them with all other moths belonging to the same families, whether they wd strike you as more brightly-coloured than the average.— Would they look an unusually handsome & gay lot? Lastly is Satyrus anthe a gaily coloured butterfly & do the sexes differ in colour?

I am aware that it is much the most probable, from there wd be so much diversity in colouring, & from its being so very difficult to decide what to call brightly-coloured, that you could give no answer. Nor do I know whether you are acquainted with the majority of the moths in the list.—

Supposing you can give a definite or nearly definite answer, what I desire is to have permission to give the answer on your authority.

I sincerely beg your pardon for being so bothersome & remain | My dear Sir | —— | C D

You will perceive the point, which I am driving at whether there is any relation between an inequality in number of the two sexes & bright or gaudy colouring, whether displayed in both sexes or in one sex, alone.—4

I am inclined to think, (& this I believe was John Hunters opinion) that this holds good, through the influence of polygamy with all secondary masculine characters in the case of mammals & Birds.5


The year is established by the relationship between this letter and the letter from Henry Doubleday, 22 April 1868.
CD refers to a list that he had drawn up using information from a sale catalogue of Lepidoptera issued in December 1866 by Otto Staudinger (see letter from Henry Doubleday, 3 April 1868 and n. 1). The list, written by an amanuensis with annotations by CD, is in DAR 81: 85–6.
CD had ticked with blue pencil the following names: Satyrus anthe (now Chazara persephone, the dark rockbrown), Zeuzera aesculi (now Z. pyrina, the leopard moth), Limacodes asellus (now Heterogenea asella, the triangle), Phragmataecia castaneae (the reed leopard), Epichnopteryx intermediella (now Psyche crassiorella), Dasychira selenitica (now Gynaephora selenitica), Lasiocampa populifolia (now Gastropacha populifolia), Agrotis labyrinthica, Dichonia aeruginea, Ortholitha cervinata, Cidaria firmata (now Thera firmata, the pine carpet), and Cidaria malvata (now Larentia malvata, the mallow).
In Descent 1: 309–13, CD discussed the proportion of the sexes in Lepidoptera, but did not mention colour in this context. CD discussed possible reasons for colour differences in insects in Descent 1: 417, 419–23.
Hunter’s comment on the relation between relative numbers of the sexes and coloration has not been identified.


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


Submits lists of insects [missing] for correspondent to check whether brightly coloured. Wants to determine whether there is any relation between bright colouring, whether in both sexes or one alone, and an unequal number of males and females.

Letter details

Letter no.
Charles Robert Darwin
Henry Doubleday
Sent from
Source of text
DAR 82: 121-2
Physical description
AdraftS 4pp

Please cite as

Darwin Correspondence Project, “Letter no. 6123,” accessed on 21 September 2021,

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