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Darwin Correspondence Project

To William Forsell Kirby   9 July [1863]

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

July 9th

Dear Sir

I am very much obliged for the copy of your Paper on Geographical Distribution, but which I had already read in the Ent. Transacts.1 I have been very much interested by it & it seems to me excellently done. There was of course much new to me; & I have been particularly struck by your observations on the Corsican sub- species & on those of N. America.—2 It would be interesting if you could get a set of specimens from the Shetland Isld & see if you could observe the faintest trace of differentiation.—

with my best thanks, I remain | Dear Sir | Yours very faithfully | Ch. Darwin

Footnotes

Kirby 1863. CD’s annotated copy of the volume of the Transactions of the Entomological Society of London in which this paper appeared is in the Darwin Library–Down; the part containing Kirby 1863 was issued in May 1863. In 1862, Kirby had written to CD telling him of his belief in the mutability of species; in reply, CD had expressed a hope that Kirby would some day ‘write on variation in Butterflies’ and express his beliefs ‘on the subject of species’ (see Correspondence vol. 10, letter to W. F. Kirby, 12 December [1862]). In his paper, Kirby discussed the geographical distribution of species and sub-species of butterflies in Europe on the basis of CD’s theory (see especially Kirby 1863, pp. 481–2 and 491).
CD refers to Kirby’s comments on the role of geographical isolation in the production of new species and sub-species of butterflies in North America and Corsica, distinct from those in continental Europe (Kirby 1863, p. 491). Kirby observed: If geologists can tell us how long Corsica has been separated from the main land, we shall have some most reliable data by which to calculate the length of time that the formation of a species requires, for a large number of Corsican insects are already good species, and many more have become sub-species, which is the last step towards the formation of a new species.

Bibliography

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

Kirby, William Forsell. 1863. On the geographical distribution of European Rhopalocera. [Read 5 January 1863.] Transactions of the Entomological Society of London 3d ser. 1 (1862–4): 481–91.

Summary

CD is particularly struck by WFK’s observations on Corsican and N. American subspecies in his paper ["On the geographical distribution of European Rhopalocera", Trans. R. Entomol. Soc. Lond. 3d ser. 1 (1862–3): [!?bib has 1862–4] 481–92]. Thinks it would be interesting for WFK to examine specimens from the Shetland Islands, for even faint trace of differentiation.

Letter details

Letter no.
DCP-LETT-4237
From
Charles Robert Darwin
To
William Forsell Kirby
Sent from
Down
Postmark
JY 10 63
Source of text
American Philosophical Society (Mss.B.D25.)
Physical description
ALS 2pp

Please cite as

Darwin Correspondence Project, “Letter no. 4237,” accessed on 23 April 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-4237.xml

Also published in The Correspondence of Charles Darwin, vol. 11

letter