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Darwin Correspondence Project

To John Jenner Weir   27 February [1868]

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

Feb 27.

My dear Sir

I must thank you for yr paper on Apterous Lepidopt: which has interested me exceedingly, & likewise for the very honourable mention which you make of my name.1 It is almost a pity that yr paper was not published in some journal in which it wd have had a wider distribution. It contained much that was new to me. I think the part about the relation of the wings & spiracles & trachæ might have been made a little clearer.2 Incidentally you have done me a good service by reminding me of the rudimentary spurs on the legs of the partridge;3 for I am now writing on what I have called sexual selection. I believe that I am not mistaken in thinking that you have attended much to birds in confinement, as well as to insects. If you cd call to mind any facts bearing on this subject with Birds, insects or any animals—such as the selection by a female of any particular male—or conversely of a particular female by a male—or on the rivalry between males—or on the allurement of the females by the males—or any such facts, I shd be most grate⁠⟨⁠ful⁠⟩⁠ for the information if you wd have the kindness to communicate it.

Pray believe me— | my dear Sir | yours very faithfully | Ch. Darwin

P.S. I may give an instance of class of facts, that Barrow asserts, that a male Emberiza(?) at the Cape has immensely long tail-feathers during breeding season; & that if these are cut off, he has no chance of getting a wife.4 I have always felt an intense wish to make analogous trials, but have never had an opportunity, & it is not likely that you or anyone would be willing to try so troublesome an experiment. Colouring or staining the fine red breast of a bull-finch, with some innocuous matter into a dingy tint wd be an analogous case, & then putting him & ordinary males with a female.

A friend promised, but failed, to try a converse experiment with white pigeons, viz to stain their tails & wings with magenta or other colours & then observe what effect such a prodigious alteration would have on their courtship.5 It wd be a fine trial to cut off the eyes of the tail-feathers of male-peacocks, but who wd sacrifice the beauty of their bird for which reason to please a mere naturalist!

C. D


Weir’s paper, ‘Apterous Lepidoptera’, opened with the remark: ‘until the Darwinian Theory was given to science, the possession by many creatures of obsolete organs formed one of the profoundest puzzles to the naturalist’ (Weir 1867, p. 3). CD’s annotated copy of the paper is in the Darwin Pamphlet Collection–CUL.
Weir described how the thoracic spiricula functioned in connection with the tracheae to inflate the wings of Lepidoptera newly emerged from the larval state (Weir 1867, p. 9).
The spurs are mentioned in Weir 1867, p. 3.
CD refers to the description of Emberiza longicauda (now Euplectes progne, the long-tailed widowbird) in John Barrow’s An account of travels into the interior of Southern Africa (Barrow 1801–4, 1: 243–4). Widowbirds are also called whydahs. CD cited Barrow’s description of the male ‘widow-bird’ in Descent 2: 97 and 98 n. 88.


Barrow, John. 1801–4. An account of travels into the interior of southern Africa, in the years 1797 and 1798. 2 vols. London: T. Cadell jun. and W. Davies.

Descent: The descent of man, and selection in relation to sex. By Charles Darwin. 2 vols. London: John Murray. 1871.

Weir, John Jenner. 1867. Apterous Lepidoptera. Greenwich: W. H. Crockford.


Thanks JJW for his paper on apterous insects [see 5939], which contained much new information.

Asks JJW for any information he may have on sexual selection.

Describes an experiment, still untried, of staining tail-feathers of male pigeons in bright colours to find the effect on courtship.

Letter details

Letter no.
Charles Robert Darwin
John Jenner Weir
Sent from
FE 27 68
Source of text
Field Museum of Natural History, Chicago
Physical description
LS(A) 6pp

Please cite as

Darwin Correspondence Project, “Letter no. 5942,” accessed on 6 February 2023,

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