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Darwin Correspondence Project

To H. W. Bates   4 May [1862]1


May 4th

My dear Mr Bates.

Hearty thanks for your most interesting letter & three very valuable extracts.2 I am very glad that you have been looking at the S. temperate insects. I wish that the materials in B. Museum had been richer, but I should think the case of the S. American Carabi, supported by some other case, would be worth a paper. To us who theorise I am sure the case is very important. Do the S. American Carabi differ more from the other species, than do, for instance, the Siberian & European & N. American & Himalayan (if the genus exists there); if they do, I entirely agree with you that the difference would be too great to account for by the recent Glacial period. I agree, also, with you in utterly rejecting an independent origin for these Carabi.—

There is a difficulty, as far as I know, in our ignorance whether insects change quickly in time; you could judge of this by knowing how far closely allied Coleoptera generally have much restricted ranges, for this almost implies rapid change. What a curious case is offered by Land-Shells, which become modified in every sub-district, & have yet retained the same general structure from very remote geological periods. When working at glacial period, I remember feeling much suprise how few Birds, no mammals & very few sea-mollusca seemed to have crossed, or deeply entered, the intertropical regions during the cold period. Insects, from what you say, seem to come under the same category. Plants seem to migrate more readily than animals.3 Do not underrate the length of Glacial period; Forbes used to argue that it was equivalent to the whole of the pleistocene period in the warmer latitudes.—4 I believe with you that we shall be driven to an older Glacial period.—5

I am very sorry to hear about B. Museum; it would be hopeless to contend against any one supported by Owen.6 Perhaps another chance might occur before very long. How would it be to speak to Owen, as soon as your own mind is made up? From what I have heard, since talking to you, I fear strongest personal interest with Minister is requisite for Pension.—

Farewell & may success attend the “acerrimo propugnatori”7   Yours very sincerely | C. Darwin

I deeply wish you could find some situation in which you could give your time to Science; it would be a great thing for science & for yourself.—


The year is established by the relationship to the letter from H. W. Bates, 30 April 1862.
See letter from H. W. Bates, 30 April 1862.
See letter from H. W. Bates, 30 April 1862 and n. 3. In Origin, p. 378, CD stated: as I believe, a considerable number of plants, a few terrestrial animals, and some marine productions, migrated during the Glacial period from the northern and southern temperate zones into the intertropical regions, and even crossed the equator. In his ‘big book’ on species, published posthumously as Natural selection, CD made more detailed remarks about the migration during the glacial period of beings other than plants (Natural selection, pp. 554–5): In mammals & reptiles, I know of no cases of the same or representative species being found in the opposite hemispheres & not in the intermedial Tropics. In Australia, … there are some striking cases of Birds, … which represent northern forms, & are not known to occur within the Tropics … In regard to insects, I carefully collected the beetles of Tierra del Fuego, … but none are identical with, or closely representative of, northern forms; … In southern Australia & New Zealand, there are only a few very doubtful cases of representatives of northern forms.... In regard to sea-shells, … I am surprised that there is not more identity or very close representation between north & south.
See Forbes 1846, p. 403. There is an annotated copy of the volume of the Memoirs of the Geological Survey in which this paper appeared in the Darwin Library–CUL.
Bates believed that the extent of the differences between species of the beetle genus Carabus in the temperate regions of North and South America was too great to have arisen since the recent glacial period (see letter from H. W. Bates, 30 April 1862). However, when Bates first described this case to CD, in 1861, CD had reminded him that some geologists had ‘speculated on a Permian & even on a Chalk Glacial period’ (see Correspondence vol. 9, letter from H. W. Bates, 28 March 1861 and CD annotations, and letter to H. W. Bates, 4 April [1861]). CD included a brief discussion of this case in his much-revised discussion of the mundane glacial period in Origin 4th ed., p. 454.
The reference is to the competition for the position of zoological assistant at the British Museum (see letter from H. W. Bates, 30 April 1862 and n. 10). Richard Owen was superintendent of the natural history collections at the British Museum and supported the application of Albert Charles Lewis Günther for the post.
CD refers to a dedication to Bates, describing him as a ‘keen and excellent defender’ of CD’s doctrines, given in Felder and Felder 1862, p. 113 (see letter from H. W. Bates, 30 April 1862 and n. 9).


Thanks for letter and "valuable" extracts.

If S. American Carabi differ more from other species than do those from other distant locations (e.g., Siberia, Europe, etc.), CD agrees that difference would be too great to have occurred in the recent glacial age; CD also rejects independent origin. Plants seem to migrate more readily than animals. HWB should not underrate length of glacial period; CD also believes they will be driven to an older glacial period.

Sorry about news of British Museum – hopeless to contend against anyone supported by Owen.

CD dearly wishes HWB could find a situation in which he could give time to science.

Letter details

Letter no.
Darwin, C. R.
Bates, H. W.
Sent from
Source of text
Cleveland Health Sciences Library (Robert M. Stecher collection).
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 3532,” accessed on 16 January 2017,