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Darwin Correspondence Project

To B. D. Walsh   [19] April [1866]

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

April 20th1

My dear Sir

I forwarded the paper at once to Wallace “9 St. Mark’s Terrace Regents Park, London. N.W.” & pray at any time use me in the same way.2

I have been much interested by your remarks on Halesidota3 & especially on the 18 spots on Doryphora.—4 What an indefatigable worker you are!

I know nothing about Mr. Wilson Armistead, except that he is going to publish on galls & consequently I sent him a good collection which I had from Ceylon:5 he was profuse in his thanks to me,6 so that I do not think it likely that he would be intentionally ungrateful to you.—

I see that you have been attacking Mr Scudder; & you will do the subject of the change of species wonderfully good service; for everyone in the U. States must now be aware that if he argues foolishly or misquotes, you will be down on him like a clap of thunder.7 I have followed Sir C. Lyell’s8 advice, (who is a very wise man) & always avoided controversy; but Lyell’s arguments (except as far as loss of time is concerned) do not apply to any third party, who has energy & courage & wit enough to enter the arena.—

My health is considerably improved so that I work 2–3 hours daily;9 but all my new work has been stopped since the 1st of March, by correcting & adding to a new Edit. of the Origin.10 But I have found that I cd. not do nearly justice to the subject. I have referred to your work, but have not used it to one quarter of the extent, which I shd. have liked to have done.11 I will send you a copy when it is published in the course of the summer; for it is somewhat improved since the American Edition, which was so unfortunately stereotyped.—12 If you can remember look in Histor: Sketch at my account of Owen’s views: it is rich & shows what a muddle those who “utter sonorous commonplaces about carrying out the Plan of Creation &c” fall into.—13

My dear Sir | Yours most sincerely | Ch. Darwin

You will have seen an account of poor Whewell’s death from a fall from a Horse.14

My second son is now at your old College of Trinity, & has just gained a Scholarship, being the second man of his year, which pleases me much.—15


CD evidently misdated the letter: the cover is postmarked 19 April 1866.
Walsh had observed four stable colour variants in the pale tussock moth, Halysidota tessellaris; the differences in colour were distinguishable at a certain stage in the development of the larvae, but not at the imago stage. On this basis, Walsh proposed a new species, H. Harrissii, arguing that species distinctions should not be made solely on the basis of comparisons between adult forms (Walsh 1864–5, pp. 197–200). He drew an analogy between the moths and the ‘alternate generations’ of certain Radiata, in which distinct hydroids produce similar jellyfish (ibid., p. 203); this passage is scored in CD’s copy (Darwin Pamphlet Collection–CUL).
Walsh described eighteen spots, arranged in a particular pattern, on the thorax of two species of Doryphora. He remarked that the presence of such identical markings was explicable if the two species had arisen from a common ancestor, whereas there was no reason for ‘Nature to plagiarize from herself a merely ornamental design’ when millions of other patterns were available (Walsh 1864–5, pp. 207–8); this section is scored in CD’s copy.
See letter from B. D. Walsh, 13 March 1866 and n. 8. CD had received galls from George Henry Kendrick Thwaites, director of the Peradiniya botanic gardens in Ceylon, in 1863 (see Correspondence vol. 11, letter to G. H. K. Thwaites, 30 March [1863] and n. 10). The galls are described in Variation 2: 282.
No correspondence between CD and Armistead has been found.
In the postscript to Walsh 1864–5, Walsh criticised a recent paper by Samuel Hubbard Scudder, in which a passage from Origin was misquoted (Walsh 1864–5, p. 216; see also Scudder 1866, pp. 26–7). Walsh concluded: ‘A theory must be strong indeed, when, as would seem from the practice of certain Naturalists, it can only be refuted by misstating it.’
Following long periods of illness in 1864 and 1865, CD began to report improvement in his health in September 1865 (see Correspondence vol. 12, and Correspondence vol. 13, letter to J. D. Hooker, 27 [or 28 September 1865]).
CD had agreed to produce a fourth edition of Origin in February (see letter to John Murray, 22 February [1866]).
CD added two references to Walsh in the fourth edition of Origin, citing his work on phytophagic forms (Walsh 1864–5), and his ‘law of equable variability’, according to which characters highly variable in one species tend to be variable in allied species (Walsh 1863, p. 213). See Origin 4th ed., pp. 55, 187.
Walsh’s name appears on CD’s presentation list for the fourth edition of Origin (see Correspondence vol. 14, Appendix IV); the book was not published until November 1866 (see letter from John Murray, 18 July [1866]). On the use of stereotypes in the production of the American edition of Origin in 1860, see the letter to Asa Gray, 16 April [1866] and n. 11.
CD considerably revised his account of Richard Owen’s work in his historical sketch to Origin 4th ed., pp. xvii–xviii (Peckham ed. 1959, pp. 64–6). See letter to J. D. Hooker, 31 May [1866] and n. 11. CD quotes from Walsh 1864–5, p. 215.
William Whewell, an acquaintance of CD’s since his undergraduate days at Cambridge, had died on 6 March 1866 (DNB). Walsh had been a student and fellow at Trinity College, Cambridge, while Whewell was fellow and junior tutor there (Alum. Cantab.).


Alum. Cantab.: Alumni Cantabrigienses. A biographical list of all known students, graduates and holders of office at the University of Cambridge, from the earliest times to 1900. Compiled by John Venn and J. A. Venn. 10 vols. Cambridge: Cambridge University Press. 1922–54.

Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 29 vols to date. Cambridge: Cambridge University Press. 1985–.

DNB: Dictionary of national biography. Edited by Leslie Stephen and Sidney Lee. 63 vols. and 2 supplements (6 vols.). London: Smith, Elder & Co. 1885–1912. Dictionary of national biography 1912–90. Edited by H. W. C. Davis et al. 9 vols. London: Oxford University Press. 1927–96.

Origin 4th ed.: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. 4th edition, with additions and corrections. By Charles Darwin. London: John Murray. 1866.

Origin: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. By Charles Darwin. London: John Murray. 1859.

Scudder, Samuel Hubbard. 1866. Revision of the hitherto known species of the genus Chinobas in North America. Proceedings of the Entomological Society of Philadelphia 5: 1–28.

Variation: The variation of animals and plants under domestication. By Charles Darwin. 2 vols. London: John Murray. 1868.

Walsh, Benjamin Dann. 1864–5. On phytophagic varieties and phytophagic species. Proceedings of the Entomological Society of Philadelphia 3: 403–30, 5: 194–216.


CD has followed Lyell’s advice and avoided controversy over Origin but encourages BDW to attack S. H. Scudder and others who argue foolishly or misquote him.

Letter details

Letter no.
Charles Robert Darwin
Benjamin Dann Walsh
Sent from
AP 19 66
Source of text
Field Museum of Natural History, Chicago (Walsh 7)
Physical description
ALS 6pp †

Please cite as

Darwin Correspondence Project, “Letter no. 5061,” accessed on 4 March 2024,

Also published in The Correspondence of Charles Darwin, vol. 14