To A. R. Wallace   17 [March 1868]1

4 Chester Place | Regents Park. | N.W. | (address for next 14 days)

17th

My dear Wallace

Many thanks about Pieridæ.2 I have no photographs up here, but will remember to send one from Down.—3 Should you care to have a large one, of treble or quadruple common size, I will with pleasure send you one under glass cover, to any address you like in London, either now or hereafter.— I grieve to say we shall not be here on April 2d. as we return home on 31st.—4 In summer I hope that Mrs Wallace & yourself will pay us a visit at Down, soon after your return to London; for I am sure you will allow me the freedom of an invalid.—5

My paper tomorrow at Linn. Soc. is simply to prove alas! that Primrose & Cowslip are as good species as any in the world, & that there is no trustworthy evidence of one producing the other. The only interesting point is the frequency of the production of natural hybrids, i.e. oxlips & the existence of one kind of oxslip, which constitute a third good & distinct species. I do not suppose that I shall be able to attend at Linn. Soc. tomorrow.—6

I have been working hard in collecting facts on sexual selection every morning in London, & have done a good deal; but the subject grows more & more complex & in many respects more difficult & doubtful.— I have had grand success this morning in tracing gradational steps by which Peacocks tail has been developed: I quite feel as if I had seen a long line of its progenitors.—7

I do not feel that I shall grapple with the sterility argument till my return home; I have tried once or twice & it has made my stomach feel as if it had been placed in a vice.— Your paper has driven 3 of my children half-mad—8 One sat up to 12 oclock over it— My second son, the mathematician,9 thinks that you have omitted one almost inevitable deduction which apparently could modify the result. He has written out what he thinks, but I have not tried fully to understand him. I suppose that you do not care enough about subject to like to see what he has written.—

I hope your Book progresses. I am intensely curious to see your paper in Murray’s Journal.10

My dear Wallace | Yours very sincerely | Ch. Darwin

1
The date is established by the relationship between this letter and the letter from A. R. Wallace, 15 March [1868].
2
In his letter of 15 March [1868], Wallace provided CD with information on brightly coloured female butterflies of the genus Pieridae.
3
On ‘cartes de visite’, see also the letter from W. B. Tegetmeier, 8 January [1868?] and n. 2. CD had a carte de visite made from a photograph taken by his son, William Erasmus Darwin, in 1864 (Carus photograph album, Smithsonian Institution Archives, Record Unit 7315), and cartes were also produced from photographs taken by Ernest Edwards in 1865 and 1866 (see Correspondence vol. 13, letter from E. A. Darwin to Emma Darwin, 25 [November 1865] and n. 3).
5
According to Emma Darwin’s diary (DAR 242), Wallace and Annie Wallace visited Down on 12 September 1868.
6
See letter from A. R. Wallace, 15 March [1868] and n. 6. CD’s paper, ‘Specific difference in Primula’, was read on 19 March 1868 at the Linnean Society. There is no evidence that CD attended the meeting.
7
For CD’s views on the development of highly complex ornamentation such as peacock feathers, see the letter to Roland Trimen, 16 January [1868], n. 5.
8
Wallace had written a short essay in which he tried to show how hybrid sterility could be produced through the action of natural selection (see enclosure to letter from A. R. Wallace, 1 March 1868).
10
CD refers to Wallace’s book The Malay Archipelago (A. R. Wallace 1869), which he had encouraged Wallace to write in order to ‘popularize’ his researches (see Correspondence vol. 14, letter to A. R. Wallace, 22 January 1866 and n. 7). CD also refers to Wallace’s paper, ‘A theory of birds’ nests’ (A. R. Wallace 1868), which appeared in the short-lived Journal of Travel and Natural History, whose founder and editor was Andrew Murrray.

Manuscript Alterations and Comments

2.1 tomorrow] after del ‘on’
2.4 i.e. oxlips] interl
2.5 suppose] after del ‘I [illeg]’
2.6 tomorrow.—] added over‘—’

Please cite as “DCP-LETT-6018,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-6018