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Darwin Correspondence Project


To B. D. Walsh   21 September 1868

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

Sep 21 1868

My dear Sir

I am very sorry that my book has never reached you, & so is Mr Murray, & he has proved his sorrow by sending off at his own cost by post this day another copy.1

I have much to thank you for: I have been glad to see Dr Scudder’s pamphlet (returned by this post) though it does not contain much.2

Judge Caton’s pamphlet is really admirable, & I have found in it much useful for my work.3

Pray thank Mr Riley for the extract about the peach trees. I have much pleasure in enclosing my photograph for him; but I do not like to take the liberty of applying to Prof. Westwood for his photograph.4

I am particularly obliged for your information about the stridulating organs; these certainly sometimes differ in the two sexes, but how far this is general I am unable to say.5

Your investigation about the Cicadas possesses extraordinary interest & the map will be a curiosity. How odd it is that individuals do not migrate from one area into another, & thus cause apparent confusion in the periods.6

I see that Scudder states that the Orthoptera stridulate differently by night & day; may not the “forced” Cicadas be dumb from coming out when the average temperature is too low;7 it wd be curious to ascertain whether the dumb individuals can breed.

With most sincere thanks for all your kindness— Believe me yours very truly | Ch. Darwin


See letter to John Murray, 16 September [1868], and letter from John Murray, 18 September [1868].
CD refers to a work by Samuel Hubbard Scudder on the stridulating organs of Orthoptera (Scudder 1867; see letter from B. D. Walsh, 29 August 1868 and n. 14). CD used information from Scudder’s paper in Descent 1: 353, 356, and 2: 331; CD mistakenly cited it as being from the April 1868 issue of the periodical, rather than from the October 1867 number (see Scudder 1867).
For CD’s use of Caton 1868, sent to him by Walsh, see the letter to J. D. Caton, 18 September 1868 and nn. 2–5.
For Charles Valentine Riley’s article on peach trees, see the enclosure to the letter from B. D. Walsh, 29 August 1868; Walsh had also asked whether CD could send Riley both his photograph and John Obadiah Westwood’s.
See letter from B. D. Walsh, 29 August 1868. For more on CD’s recent investigations into stridulating organs, see the letter to A. R. Wallace, 16 September [1868] and nn. 2 and 3.
See letter from B. D. Walsh, 29 August 1868.
Scudder wrote that the day and night songs were different only in some species; see Scudder 1867, pp. 309–10, for the differing songs. On the ‘forced’ cicadas, see the letter from B. D. Walsh, 29 August 1868.

Letter details

Letter no.
Darwin, C. R.
Walsh, B. D.
Sent from
Source of text
Field Museum of Natural History, Chicago (Walsh 14)
Physical description


Thanks BDW for pamphlets [by S. H. Scudder and J. D. Caton].

His information about Cicada is of extraordinary interest. Discusses stridulation organs which certainly sometimes differ in the sexes. CD would be curious to know if "dumb" Cicada can breed.

Please cite as

Darwin Correspondence Project, “Letter no. 6382,” accessed on 14 February 2016,