Ɛpsilon

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

ADraftS

1
The year is established by the relationship between this letter and the letter from Henry Doubleday, 22 April 1868.
2
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.
3
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, Cidaria firmata (now Pennithera firmata, the pine carpet), Ortholitha cervinata and Cidaria malvata (both synonyms of Larentia malvata, the mallow).
4
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.
5
Hunter’s comment on the relation between relative numbers of the sexes and coloration has not been identified.

Manuscript Alterations and Comments

0.1 April 15th] added pencil
1.2 & I … will you 1.3] interl above del ‘would you be so good as to’
1.2 know] after del ‘well’
1.3 list] after del ‘enclosed’
1.4 curious] after del ‘extremely’
1.4 two points] aftered from ‘one point’
1.5 are] above del ‘is’
1.5 of importance to] altered from ‘important for’
1.5 endeavoured] after del ‘vainly’
1.6 failed] before del ‘so’
1.6 being used] interl
1.7 first] interl
1.7 whether] after del ‘about which I am curious is, firstly’
1.7 12] altered from ‘11’
1.7 of moths] interl
1.7 [TICK]] in blue crayon
1.8 ie colour … bright colour) 1.9] interl
1.9 purple] interl
1.9 colour] above del ‘colour’
1.9 as the] added after del ‘as the or even as conspicuous is anyway.’
2.1 the] altered from ‘these’, after del ‘all’
2.1 (ie] after interl & del ‘eleven’
2.1 the 130] added before del ‘those’
2.2 other] after del ‘the’
2.2 belonging to] above del ‘of’
2.3 families] altered from ‘family’
2.4 Would … in colour? 2.5] added
3.1 much the] interl
3.1 from] above del ‘that’
3.2 from its being] above del ‘it is’
3.2 very] interl
3.3 Nor] after del ‘And perhaps you are not’
3.4 majority] ‘a’ over illeg
4.1 nearly definite] interl
5.1 I] after del ‘Lastly’
5.1 sincerely] after del ‘must most’
5.1 remain] after del ‘I’
6.2 an inequality] after del ‘the’
6.2 two] interl
6.2 whether displayed] above del ‘either’
7.1 I believe] interl
7.2 masculine] above del ‘sexual’
7.2 in the case of 7.3] above del ‘with’

Please cite as “DCP-LETT-6123,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-6123