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Darwin Correspondence Project

From J. O. Westwood   26 September 1861


26 September | 1861

My dear Mr Darwin

I have succeeded in finding the reference to Morren’s paper1 which appeared in the Horticulteur Belge about 1835 & of which an abstract was given in the Trans. Ent. Soc. 1. Proc. p xliv & xlix2   It is entitled “On the Agency of insects in causing Sterility in flowers by the removal of the masculine organs observed among the Asclepiadeæ.” The insects observed were our common white butterflies the tarsi of which were loaded with the pollen masses of the plants in question—not Orchideæ.3

If you could conveniently let my little box be left either at Van Voorst’s Paternoster Row—or the British Museum I should get it in time4

Yours very truly | J. O. Westwood

CD annotations

2.1 If … time 2.2] crossed ink
Top of first page: ‘Dichogamy’5 brown crayon
Verso of last page: ‘Mr Westwood sent me 2 large Hymenopt. insects *from N. America [interl] with numerous pollinia on their feet; & Mr Gosse told me he had seen probosces of Sphingidæ with them in N. America.’6 ink


Westwood had first mentioned a paper by Charles François Antoine Morren on orchids and insects in a letter (now missing) of 1860 (see Correspondence vol. 8, letter to J. O. Westwood, 9 July [1860]). CD had asked Westwood to give him a precise reference to the paper (see letters to J. O. Westwood, 15 August [1861] and 4 September [1861]). CD also asked for this information in the first of two letters to the Gardeners’ Chronicle, [before 14 September 1861].
Westwood published this information in the Gardeners’ Chronicle and Agricultural Gazette, 5 October 1861, p. 889. CD did not refer to this paper of Morren’s in Orchids, but he did cite another of Morren’s papers (Morren 1839). See Orchids, p. 270 n.
CD had asked Westwood to send him any specimens of moths that had orchid pollen-masses attached to them (letter to J. O. Westwood, 15 August [1861]). Westwood had sent CD two insects, but CD discovered that the pollen-masses did not actually belong to orchids (see letter to J. O. Westwood, 4 September [1861]). Westwood refers to the publishing house of John Van Voorst.
Dichogamy is the condition in which the stamens and pistils of a hermaphrodite plant mature at different times, thereby preventing self-fertilisation. Most of CD’s notes on dichogamy are in DAR 49, 76, and 205.8.
Philip Henry Gosse spent twelve years in North America. His work on the entomology of Newfoundland remained unpublished, but his observations on the natural history of Canada were published in Gosse 1840 (DNB).


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 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.

Gosse, Philip Henry. 1840. The Canadian naturalist. A series of conversations on the natural history of lower Canada. London.

Morren, Charles François Antoine. 1836. On the agency of insects in causing sterility in flowers by the removal of the masculine organs, observed amongst the Asclepiadeæ. Transactions of the Entomological Society 1: Proceedings, pp. xliv–xlv. [Vols. 8,9]

Morren, Charles François Antoine. 1839. On the production of vanilla in Europe. Annals and Magazine of Natural History 3: 1–9.

Orchids: On the various contrivances by which British and foreign orchids are fertilised by insects, and on the good effects of intercrossing. By Charles Darwin. London: John Murray. 1862.


Has found the reference to Charles Morren’s paper, "On the agency of insects in causing sterility in flowers" [Proc. R. Entomol. Soc. Lond. 1 (1836): xliv–xlv].

Common white butterflies remove pollen-masses with their tarsi from plants of the Asclepiadaceae.

Letter details

Letter no.
John Obadiah Westwood
Charles Robert Darwin
Sent from
Source of text
DAR 181: 89
Physical description
3pp †

Please cite as

Darwin Correspondence Project, “Letter no. 3267,” accessed on 2 July 2020,

Also published in The Correspondence of Charles Darwin, vol. 9