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Darwin Correspondence Project

To H. W. Bates   9 May [1862]1

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

May 9th

Dear Bates

I have been talking in London with Sir C. Lyell & he told me facts showing that there almost certainly must have been a Glacial Miocene period!2 In N. Italy he has seen huge boulders embedded with Miocene shells!—3

I saw at B. Museum the admirable mimetic case of Philippine Longicorn & Curculia— Really wonderful.— The gentlemen at the Museum sucked in your doctrine in explanation as easily as mother’s milk.4 I saw, also, there Mr Baily(?) & he showed me the generative organs of closely allied Chrysomelæ— on my word it is a very curious & unpleasant case, for he vows that these parts never vary.—5 Dr. Günther, I find, is the candidate for place in B. Museum, & I apprehend no one would have a chance against him.—6 I hear also with much surprise that a candidate would have to pass a civil-service examination.—7

Good Night | I am tired— | Yours sincerely | C. Darwin


The year is established by the relationship to the letter from H. W. Bates, 30 April 1862.
See letter to H. W. Bates, 4 May [1862] and n. 5. CD was in London from 6 to 9 May 1862 (Emma Darwin’s diary (DAR 242)), during which time he met with Charles Lyell (see letter to J. D. Hooker, 9 May [1862]).
Lyell recorded observations of this phenomenon while travelling in northern Italy during September 1857 (see K. M. Lyell ed. 1881, 2: 265–8).
CD refers to the application to mimetic beetles of Bates’s explanation of mimetic resemblances in Amazonian butterflies as given in Bates 1862a. Bates argued that such resemblances could not be explained as purely the result of adaptations to similar conditions. He proposed that the imitated form was probably ‘unpalatable to insect enemies’, and, invoking natural selection, suggested that the ‘selecting agents’ were insectivores that destroyed any varieties not sufficiently resembling the unpalatable analogical form (Bates 1862a, pp. 510–12). In his review of Bates 1862a, CD stated: ‘Mr. Waterhouse has noted an excellent instance (and we have seen the specimens) of a rare beetle inhabiting the Philippine Archipelago, which most closely imitates a very common kind belonging to a quite distinct group’ (‘Review of H. W. Bates on mimetic butterflies’, p. 221; see also Collected papers 2: 89); the reference is to the entomologist George Robert Waterhouse, who was keeper of the geology department at the British Museum.
Bates had told CD in 1861 of Joseph Sugar Baly’s claim that the male organs of generation of Chrysomelidae could be used to distinguish one species from another (see Correspondence vol. 9, letter from H. W. Bates, 18 March 1861).
The reference is to the vacancy for a zoological assistantship at the British Museum for which Bates hoped to be considered (see letter from H. W. Bates, 30 April 1862 and n. 10, and letter to H. W. Bates, 4 May [1862]). Albert Charles Lewis Günther was appointed to the post in July 1862 (Gunther 1975, p. 308 n. 1).
Examinations for appointment to the civil service had been introduced in 1855 (EB). However, Günther did not have to sit the examination: at the instigation of the principal librarian, Anthony Panizzi, the Superannuan Act was invoked to provide Günther with a level of seniority that rendered him unaffected by established requirements (Gunther 1975, p. 297).


Bates, Henry Walter. 1862. Contributions to an insect fauna of the Amazon valley. Coleoptera: Longicornes. Annals and Magazine of Natural History 3d ser. 9: 117–24, 396–405, 446–58.

Collected papers: The collected papers of Charles Darwin. Edited by Paul H. Barrett. 2 vols. Chicago and London: University of Chicago Press. 1977.

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

EB: The Encyclopædia Britannica. A dictionary of arts, sciences, literature and general information. 11th edition. 29 vols. Cambridge: Cambridge University Press. 1910–11.


Referring to conversation with Lyell, CD is certain that there was a Miocene glacial period.

Compliments HWB on the mimetic display at the British Museum. Those at the Museum readily accepted HWB’s "doctrine".

Was shown genital organs of closely allied Chrysomelidae.

Albert Günther is candidate for position at Museum.

Letter details

Letter no.
Charles Robert Darwin
Henry Walter Bates
Sent from
Source of text
Cleveland Health Sciences Library (Robert M. Stecher collection)
Physical description
ALS 3pp

Please cite as

Darwin Correspondence Project, “Letter no. 3540,” accessed on 12 September 2023,

Also published in The Correspondence of Charles Darwin, vol. 10