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Darwin Correspondence Project

From Benjamin Dann Walsh   29 April – 19 May 1864

Rock. Island. Illinois. U.S.

April 29. 1864

Chas Darwin Esq. Dear Sir,

More than thirty years ago I was introduced to you at your rooms in Christ’s College by A. W. Griesbach1 & had the pleasure of seeing your noble collection of British Coleoptera.2 Some years afterwards I became Fellow of Trinity & finally gave up my fellowship, rather that go into Orders, & came to this Country.3 For the last 5 or 6 years I have been paying considerable attention to the insect Fauna of U.S., some of the fruits of which you will see in the enclosed pamphlets.4

Allow me to take this opportunity of thanking you for the publication of your Origin of Species,5 which I read three years ago by the advice of a Botanical friend, though I had a strong prejudice against what I supposed then to be your views. The first perusal staggered me, the second convinced me, & the oftener I read it the more convinced I am of the general soundness of your theory.

As you have called upon Naturalists that believe in your views to give public testimony of their convictions,6 I have directed your attention on the outside of one or two of my Pamphlets to the particular passages in which ⁠⟨⁠I⁠⟩⁠ have done so.7 You will please accept these Papers from me in token of my respect & admiration.

As you may see from the latest of these Papers, I ⁠⟨⁠have⁠⟩⁠ recently made the remarkable discovery that there ⁠⟨⁠are the⁠⟩⁠ so-called “three sexes” not only in social insects but ⁠⟨⁠also in the⁠⟩⁠ strictly solitary genus Cynips.8

When is your great work to make its appearance?9 ⁠⟨⁠I should be⁠⟩⁠ much pleased to receive a few lines from you on th⁠⟨⁠  ⁠⟩⁠ ⁠⟨⁠    ⁠⟩⁠10

Very truly yours, Benj. D. W⁠⟨⁠alsh⁠⟩⁠

P.S. May 19. The above was written some weeks ago, but the package containing it, which is going to Rev. Hamlet Clark, does not leave till today.

CD annotations11

Verso: ‘Cynips— sexualapparatus | same part variable in allied species | Insect Poison | Ask about galls—’ pencil


As an undergraduate, CD had rooms at Christ’s College, Cambridge, from 1828 to 1831 (Freeman 1978). Alexander William Griesbach was a student at Trinity College at the same time as Walsh (Alum. Cantab.).
For CD’s interest in insect-collecting while at Cambridge, see, for example, Correspondence vol. 1, letters to W. D. Fox, [26 February 1829], [15 October 1829], and [13 January 1830]; see also Browne 1995, pp. 99–104.
Walsh was a fellow at Trinity College, Cambridge, in 1833 (DAB); until 1871, most fellows at Oxford and Cambridge Universities were required to be ordained as clergy in the Church of England (Brooke 1993, pp. 99–106). Walsh emigrated to the United States in 1838 or 1839 (DAB).
The Darwin Pamphlet Collection–CUL contains five articles by Walsh published before April 1864: Walsh 1862a, 1862b, 1863a, 1863b, and 1864a. Each article is inscribed by the author and annotated by CD.
In Origin, p. 482, CD wrote: ‘Whoever is led to believe that species are mutable will do good service by conscientiously expressing his conviction; for only thus can the load of prejudice by which this subject is overwhelmed be removed.’
On the cover of four of the five articles sent (see n. 4, above), Walsh followed his inscription with page numbers; in each of these articles, CD scored paragraphs on these pages, many of which discussed CD’s theory. The pages Walsh directed CD’s attention to were Walsh 1862a, p. 383, Walsh 1863a, pp. 213–19, Walsh 1863c, pp. 294–8, and Walsh 1864a, pp. 461–2. CD cited these four articles in his later work: see Origin 4th ed., pp. 55–6, 187; Variation 2: 283, 351–2; and Descent 1: 314, 361. For Walsh’s and other North American entomologists’ support of CD’s theory, see Sorensen 1995, pp. 197–213, 247, and 255.
Walsh refers to Walsh 1864a, ‘On dimorphism in the hymenopterous genus Cynips’ (see nn. 4 and 7, above). In the paper, Walsh argued that the gall insect Cynips quercus aciculata, hitherto regarded as a distinct species, was a female form of C. q. spongifica (Walsh 1864a, pp. 447–8).
CD’s announced intention in 1859 was to present a more detailed work of which Origin was just an abstract (see Origin, pp. 1–2). The first part of his intended work was Variation, which did not appear until 1868. The other parts planned (see Variation 1: 4–10) were never completed.
CD wrote to Walsh on 21 October [1864].
CD’s annotations refer to subjects discussed in his letter to Walsh of 21 October [1864], and to topics covered in Walsh 1864a, ‘On dimorphism in the hymenopterous genus Cynips’.


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.

Brooke, Christopher N. L. 1993. A history of the University of Cambridge, 1870–1990. Vol. 4 of A history of the University of Cambridge, general editor Christopher N. L. Brooke. Cambridge: Cambridge University Press.

Browne, Janet. 1995. Charles Darwin. Voyaging. Volume I of a biography. New York: Alfred A. Knopf.

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

DAB: Dictionary of American biography. Under the auspices of the American Council of Learned Societies. 20 vols., index, and 10 supplements. New York: Charles Scribner’s Sons; Simon & Schuster Macmillan. London: Oxford University Press; Humphrey Milford. 1928–95.

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

Freeman, Richard Broke. 1978. Charles Darwin: a companion. Folkestone, Kent: William Dawson & Sons. Hamden, Conn.: Archon Books, Shoe String Press.

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.

Sorensen, W. Conner. 1995. Brethren of the net. American entomology, 1840–1880. Tuscaloosa and London: University of Alabama Press.

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

Walsh, Benjamin Dann. 1862a. List of the Pseudoneuroptera of Illinois contained in the cabinet of the writer, with descriptions of over forty new species, and notes on their structural affinities. Proceedings of the Academy of Natural Sciences of Philadelphia (1862), pp. 361–402.


Recalls being introduced to CD when [undergraduate] at Cambridge.

Sends CD some of his pamphlets

and expresses support of Origin.

Has discovered there are "3 sexes" in the solitary Cynips as well as social insects.

Letter details

Letter no.
Benjamin Dann Walsh
Charles Robert Darwin
Sent from
Rock Island, Ill.
Source of text
DAR 181: 9
Physical description
ALS 2pp damaged †

Please cite as

Darwin Correspondence Project, “Letter no. 4477,” accessed on 9 June 2023,

Also published in The Correspondence of Charles Darwin, vol. 12