Ɛpsilon

To A. R. Wallace   5 September [1877]1

Down, | Beckenham, Kent. | Railway Station | Orpington. S.E.R.

Sept 5

My dear Wallace

“Conscious” seems to me much better than “voluntary”. Conscious action, I presume comes into play when 2 males fight for a female; but I do not know whether you admit that for instance the spur of the cock is due to sexual selection.2

I am quite willing to admit that the sounds & vocal organs of some males are used only for challenging, but I doubt whether this applies to the musical notes of Hylobates or the howling (I judge chiefly from Rengger) of the American monkeys.—3 In no account that I have seen of the stridulation of male insects shows that it is a challenge.— All those who have attended to birds consider their song as a charm to the females & not as a challenge. As the males in most cases search for the females I do not see how their odoriferous organs will aid them in finding the females.

But it is foolish in me to go on writing, for I believe I have said most of this in my book: anyhow I well remember thinking over it.— The “belling” of male stags, if I remember rightly, is a challenge, & so I daresay is the roaring of the lion during the breeding season.—4

I will just add in reference to your former letter that I fully admit with birds that the fighting of the males cooperates with their charms; & I remember quoting Bartlett that gaudy colouring in the males is almost invariably concomitant with pugnacity.5 But thank Heavens what little more I can do in science will be confined to observation on simple points. However much I may have blundered, I have done my best, & that is my constant comfort.—

Most truly yours C. Darwin

1
The year is established by the relationship between this letter and the letter from A. R. Wallace, 3 September 1877.
2
See letter from A. R. Wallace, 3 September 1877. CD and Wallace disagreed about the relative importance of natural and sexual selection in the development of a range of secondary sexual characteristics. Wallace had sent CD an advance copy of a paper arguing for the primacy of natural selection in the development of colour and pattern in animals (A. R. Wallace 1877).
3
CD’s annotated copy of Johann Rudolph Rengger’s account of the animals of Paraguay (Rengger 1830) is in the Darwin Library–CUL; CD made a marginal note (p. 21) that one species of monkey made noise ‘merely for pleasure’ (Marginalia rev. ed.). CD referred to Rengger’s account of the calls of American monkeys in Descent 2: 277 and 336. Hylobates is a genus of gibbons.
4
CD discussed the bellowing of stags and roaring of male lions in breeding season in Descent 2: 274–7.
5
Abraham Dee Bartlett was superintendent of the Zoological Gardens, London. CD cited both Bartlett and John Jenner Weir in his discussion of male display, but it was Weir who noted the coincidence of striking plumage with pugnacity (Descent 2: 93).

Manuscript Alterations and Comments

1.3 for instance] interl
1.3 is] after del ‘&c’
2.4 shows … is] interl
2.6 in most cases] interl
4.1 in] after del ‘that I’
4.4 what] ‘w’ over ‘I’

Please cite as “DCP-LETT-11127,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-11127