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Darwin Correspondence Project

From A. G. Butler   29 June 1871

17 Oxford Road, Ealing

29th. June 1871

Dear Sir

I am afraid you will be quite sick of me & my butterflies, but, whilst sketching the moth (of which part is given below) for one of my plates I was struck with the strong analogy between the marginal ocelli & those on the Argus-pheasant & I thought you might be interested by a sight of it;1

[DIAG HERE]

the gradations between the perfect & imperfect ocelli seem to point to the manner in which the former have been developed from the latter; all the species of Brahmæa are similarly ocellated, but B. Swanzyi & perhaps B. lucinæ* are the only species which exhibit an approach to the ball & socket ocellation.2

I think I may be wrong in my supposition respecting the identity of Elymnias Kamara & E. Ceryx, I find that Mr. Wallace has described a ♂ E. Ceryx which he says only differs from the ♀ in its darker colouring; still the ♀ of E. Kamara ought, judging by analogy, to be not unlike it.3

There is a curious example in the B. M. Coll. of ‘Natura facit saltum’4 a black form of Junonia Sophia Fabr. which looks exactly like a very small example of Panopea Lucretia Cramer; the ordinary colouring of J. Sophia is tawny, with brown or blackish bars across the wings; both species occur at Sierra Leone, yet it cannot be a case of mimicry since the black form is abnormal & the Panopea is itself a bad mimic of an Acrœa; I think however that such a variety, if necessary to the preservation of the species (i.e if J. Sophia were persecuted & P. Lucretia a protected form) might be retained & a mimic comparatively suddenly created.5

Many of Mr. Higgins’ ideas about the formation of markings on butterflies were based upon the notion that the wings of a butterfly were folded within the pupa, this is of course an error, the wing is of the same shape within the pupa as in the imago.6

I see that you often speak, in ‘Sexual Selection’, of the pugnacity of the ♂ Stickle-back during the breeding season7   I used to be much annoyed by it when a boy, for I always went to the Wandsworth-ponds with the intention of only bringing home the pretty Stickle-backs & I generally threw away most of the females; in two or three days all, or all but one of my fish were dead, many of them being struck in the eye by the spines of their companions.

Believe me to be | yours very sincerely | A G Butler.

*Brahmæa lucina is a species known only from Drury’s figure   See P. Z. S. 1866. p. 121.8

Ch. Darwin Esqre. FRS &c

CD annotations

Beside diagram: ‘Ask to look’ pencil

Footnotes

See letters from A. G. Butler, 26 May 1871 and 2 June 1871. Butler refers to plates for his Lepidoptera exotica (Butler 1874; see letter from A. G. Butler, 2 June 1871 and n. 12). In Descent 2: 141–51, CD discussed the gradation from elliptical spots to perfect ball-and-socket ocelli on the wings of the Argus pheasant and hypothesised that they developed as a result of sexual selection.
In Butler 1874, pp. 78–9, Butler described the gradation of ocelli in Brahmaea swanzii (now Dactyloceras swanzii) and B. lucina (now D. lucina) and suggested that the feature had developed by sexual selection.
See letter from A. G. Butler, 2 June 1871 and n. 7. Butler refers to Alfred Russel Wallace and Wallace 1869e, p. 326.
Butler reverses the adage ‘natura non facit saltum’: nature does not make jumps (Latin). B. M. Coll.: British Museum Collection.
Junonia sophia is the little commodore; Panopea lucretia (now Pseudacraea lucretia) is the false diadem. Butler noted the existence of the alternative form of J. sophia in Butler 1869, p. 76.
Henry Hugh Higgins had tried to ascertain whether the developed spots of an adult butterfly bore any relation to the lines along which its wings were folded while in a pupal state (see Higgins 1868, p. 324).
See Descent 2: 2.
Butler refers to the figure in Dru Drury’s Illustrations of natural history (Drury 1770–82, 3: pl. 34 fig. 1). Butler’s own drawing after the figure appeared in Butler 1866, p. 121.

Summary

Resemblance of ocelli, in a moth and the argus pheasant.

Mimicry.

Pugnacity of stickleback.

Letter details

Letter no.
DCP-LETT-7839
From
Arthur Gardiner Butler
To
Charles Robert Darwin
Sent from
Ealing
Source of text
DAR 89: 81–2
Physical description
4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 7839,” accessed on 17 July 2019, https://www.darwinproject.ac.uk/letter/DCP-LETT-7839.xml

Also published in The Correspondence of Charles Darwin, vol. 19

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