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Darwin Correspondence Project

To Henry Doubleday   20 March [1868]1

4. Chester Place | Regents Park | N.W. | (address till April. 1)

March. 20

My dear Sir

You have been so very kind in offering to aid me that I apply once again.—2 I was told at B. Mus. that you had made observations on Anobium tesselatum & had sent living specimens there. I was told that you had stated (& Mr F. Smith in consequence observed the same fact) that the ticking sound is a sexual call.3 Is it made first or principally by the male, & answered by the female? The answering by the female seems to make the case different from the music of the Orthoptera & Homoptera.4

I am interested by this case, as it is the first of which I have heard of noises emitted by Coleoptera for sexual purposes. Is the noise made by the thorax or head hitting against the wood?

I think that I mentioned to you that I inferred from a letter from Dr. Wallace of Colchester,—that he supposed that the statements by Mr Stainton & others that they bred more females than males from caterpillars, might be accounted for by these collectors collecting the largest & finest caterpillars. But this was an error on my part, & Dr. W. maintains that collectors collect equally large & small caterpillars;5 so that I am all astray again, & can in no way conceive why these gentlemen shd have had such different results when collecting free insects & breeding them.

Do you agree with Dr. Wallace that collectors wd collect indifferently large & small caterpillars?—

My dear Sir | Yours sincerely obliged | Ch. Darwin


The year is established by the relationship between this letter and the letter from Henry Doubleday, 28 March 1868.
The references are to the death-watch beetle, now Xestobium rufovillosum, and to Frederick Smith, an entomologist at the British Museum. See letter from Henry Doubleday, 28 March 1868 and n. 1.
In the orders Orthoptera (grasshoppers and crickets) and Homoptera (cicadas and leafhoppers), males of several species produce sounds to attract females, but females are silent.
CD refers to Alexander Wallace and Henry Tibbats Stainton. See letter to Henry Doubleday, 1 March [1868] and nn. 3 and 4.


CD asks about HD’s observation of sexual call of Coleoptera.

Also comments on statements by collectors that they breed more females than males from caterpillars. CD had thought this might be accounted for by the collection of largest and finest caterpillars, but Alexander Wallace says the collectors take large and small equally. Does HD agree with Wallace?

Letter details

Letter no.
Charles Robert Darwin
Henry Doubleday
Sent from
London, Chester Place, 4
Source of text
American Philosophical Society (Mss.B.D25.)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 6027,” accessed on 24 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 16