To Roland Trimen   16 January [1868]1

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

Jan. 16th

My dear Mr Trimen

I really do not know how to thank you enough for all the great trouble which you have taken for me.— I never saw anything so beautiful as your drawings.2 I have examined them with the microscope!! When I asked for a sketch I never dreamed of your taking so great trouble.— Your letter & Proof-sheet give me exactly & fully the information which I wanted.3

I am very glad of the description of the ocellus in the S. African Saturnidæ: I had no idea it was so complex.—4 If you know of any case in Lepidoptera of ocelli regularly confined to the male, I shd. much like to hear of it, as it would illustrate a little better the case of the peacock, which has often been thrown in my teeth.—5 I doubt whether such cases exist, & if I do not hear I will understand that you know of no such case.

Again let me thank you cordially for your great kindness, & I remain. | Yours very sincerely | Ch. Darwin

1
The year is established by the relationship between this letter and the letter from Roland Trimen, 13 January 1868.
2
Trimen enclosed a sketch showing variation in the ocelli of the South African butterfly Cyllo leda (now Melanitis leda) with his letter of 13 January 1868.
3
Trimen enclosed proof-sheets from Trimen 1862–6, containing information on Cyllo leda, with his letter of 13 January 1868. See letter from Roland Trimen, 13 January 1868 and n. 2.
4
Trimen described the ocelli on several members of the moth family Saturniidae, including one species with nine distinct rings, in his letter of 13 January 1868.
5
George Douglas Campbell, the duke of Argyll, discussed the peacock’s plumage as an example of a beautiful structure that could only have arisen from God’s design (see Campbell 1867, pp. 203–4). CD used cases of gradation in males of allied gallinaceous species to argue that highly complex ornaments, such as the ocelli of the male peacock, could have been acquired by small successive steps. See Variation 2: 135–41. CD had once written to Asa Gray, with reference to the difficulties of explaining particular structures through natural selection: ‘The sight of a feather in a peacock’s tail, whenever I gaze at it, makes me sick!’ (Correspondence vol. 8, letter to Asa Gray, 3 April [1860]). See also Correspondence vol. 15, letter to A. R. Wallace, 29 April [1867], and letter to Charles Kingsley, 10 June [1867]. CD discussed why certain features such as the peacock’s tail might be transmitted to males of the species rather than females in Origin 4th ed., pp. 240–1. CD’s notes on the peacock’s tail are in DAR 84. See also letter from Roland Trimen, 13 January 1868, n. 11.

Manuscript Alterations and Comments

2.3 regularly] interl

Please cite as “DCP-LETT-5790,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-5790