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Darwin Correspondence Project

From Thomas W. Wood   14 June 1870

221 Stanhope Street, | Hampstead Road N.W.

June 14th 1870.


I hope you will excuse the liberty I take in writing to you, but, having consulted with my friend Mr Bates,1 he has told me that you would take an interest in the facts I wish to communicate.

The letter to the Field enclosed will speak for itself & although I feel convinced of the truth of your theory of the origin of Species I think that such a fact as that mentioned about the Argus cannot be explained by it, but seems to point to (& almost to prove) the existence of a great artistic power.2 The diagram was badly printed, so I have touched it up a little & can get you the block if you would like to make use of it in your forthcoming volume, in which as I understand from Mr Bates, you have alluded to my discovery of the disguise assumed by the Orangetip butterfly when at rest.3 Have you seen it in nature? If not allow me to advise you to search along the hedgerows at dusk on the little white flowers, as I am sure you would be delighted to see the absolute perfection of the imitation of the flower by the butterfly. The season, however, for both flower & butterfly will soon be over, May being the best time.

May I also be allowed to call your attention to my article on “the courtship of birds” in the Student for April in which you will find some peculiarities of the males illustrated by a coloured picture & woodcuts.4

I have the honour to remain | Sir, | Your obedient servant, | T. W. Wood.

Charles Darwin Esq. F.R.S. &c. &c.


Henry Walter Bates.
The enclosure is at DAR 84.1: 174. In the Field newspaper, 28 May 1870, p. 457, Wood argued that since when the Argus pheasant displayed his wing-feathers like a fan, those nearest the body stood more upright than the outer ones, the shading of the ball-and-socket ocelli ought to be slightly different on the different feathers in order to preserve the three-dimensional illusion. Wood thought that this was indeed the case. See Descent 2: 143–4 n. 48, where CD discussed this point, and said that he could not see any difference in the shading. There is a draft of the note in Descent in the hand of an amanuensis in DAR 84.2: 224; it continues with two sentences not included in Descent: ‘I may however add that on a few of the basal ball & socket ornaments on the outermost feathers the shading did appear slightly difft. N.B. on the outermost secondaries the external ring is broken at the summit.’ The Argus pheasant is now the great Argus, Argusianus argus.
See Descent 1: 394 and n. 6; CD observed that the undersides of the wings of the orange-tip butterfly (Anthocharis cardamines) resembled the flower-head of wild parsley, on which it rested at night.


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

Wood, Thomas W. 1870. The courtship of birds. Student and Intellectual Observer 5 (1870–1): 113–25.


Orange-tip butterfly at rest imitates a flower.

The argus pheasant cannot be explained by natural selection.

Letter details

Letter no.
Thomas William Wood
Charles Robert Darwin
Sent from
London, Hampstead Rd
Source of text
DAR 181: 147
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 7229,” accessed on 8 April 2020,

Also published in The Correspondence of Charles Darwin, vol. 18