Letter (WCP4079.4026)


From "Von Buch on the Flora of the Canaries".1 "On continents the individuals of one kind of plant disperse themselves very far, and by the difference of stations of nourishment & of soil produce varieties which at such a distance not being crossed by other varieties and so brought back to the primitive type, become at length permanent and distinct species. Then if by chance in other directions they meet with an other variety equally changed in its march, the two are become very distinct species and are no longer susceptible of intermixture".

P.S. "Natural Selection" explains almost everything in Nature, but there is one class of phenomena I cannot bring under it,— the repetition of the forms & colours of animals in distinct groups, but the two always occurring in the same country & generally on the very same spot.2 These are most striking in insects, & I am constantly meeting with fresh instances. Moths resemble butterflies of the same country — Papilios3 in the east resemble Euploeas,4 in America Heliconius.5 At Amboyna6 I took on the same tree at the same time two longicorns7 of distinct genera, but so alike in colour & markings that I only separated them after some days — Here also & at Macassar8 occurs together a Malacoderm9 & an Elater10 of exactly the same tints of metallic blue & soft orange [2] & also similarly striate,— yet there is no affinity between them.10a A few days ago only I took a new & curious little Cicindela11 which so closely resembles in size & markings a Therates12 occurring with it, that I never know which it is till I take it out of my net;— yet there is no sign of a change in the structural characters which separate these genera. It seems to shew that colour, markings & texture of surface depend strictly on local conditions — Home Entomologists might do something in experiments on breeding insects, varying conditions of food[,] light[,] heat[,] &c as much as they will bear. In domestic var[ietie]s. have you discovered what tends to produce white, black, or particular coloured variations? or what tends to produce spots rather than stripes.

ARW. [signature]

13It is like Electric organ in orders of fishes14

Hemp seed on Birds15

Toads — poison on Parrot[']s feather16

Colour correlated with other peculiarities

a. This letter fragment was dated by the Darwin Correspondence Project as "[December? 1860]". However, see endnote 10a.
Having observed imitation of shape and colouring in butterflies and beetles (or mimicry), ARW did not believe that natural selection could account for such phenomena. After later observing mimicry in birds and reading his friend Henry Walter Bates’ paper on butterflies in the family Heliconidae, he came to believe that natural selection could account for mimicry. See Bates, H. W. 1861. Contributions to an insect fauna of the Amazon valley (Lepidoptera: Heliconidae). Transactions of the Linnean Society of London, 23: 495-566 (read 21 November 1861).
Papilio, a genus of swallowtail butterfly.
Euploea, a genus of milkweed butterflies.
A genus of brush-footed butterflies.
An island in Indonesia, part of the Moluccas, or Maluku Islands.
Longhorn beetles in the family Cerambycidae.
A city on the island of Celebes (now Sulawesi).
A beetle of the former group Malacodermata (or Malacodermi).
A genus of click beetle.
A genus of tiger beetle.
10a. The same pair of mimetic species appears to be mentioned on page 93 of his book Wallace, A. R. 1870. Contributions to the Theory of Natural Selection. A Series of Essays. London & New York: Macmillan & Co.: "In the Island of Celebes [Sulawesi] I found one of this group, having the whole body and elytra of a rich deep blue colour, with the head only orange; and in company with it an insect of a totally different family (Eucnemidae) with identically the same colouration, and of so nearly the same size and form as to completely puzzle the collector on every fresh occasion of capturing them." Given the comment in this letter that he found these species "Here also & at Macassar" and in his book he said they were from Sulawesi, it is possible that he wrote the letter in c. June 1859 whilst he was in the Manado region of northern Sulawesi. It may therefore be a reply to Darwin's letter of 6 April 1859 (WCP1842).
The text from "It is like Electric organ" to "other peculiarities" is in the hand of Charles Darwin.
Darwin had noted the difficulty to his theory of the origin of electric organs in fish. See Darwin, C. 1859. On the origin of species by means of natural selection. London: John Murray [pp. 192-194].
Darwin later noted that "[i]t is well known that hemp-seed causes bullfinches and certain other birds to become black". See Darwin, C. 1868. The variation of animals and plants under domestication. Vol. 2. London: John Murray [p. 280].
Darwin later wrote in Variation of Animals and Plants Under Domestication: "Mr. Wallace has communicated to me some much more remarkable facts of the same nature. The natives of the Amazonian region feed the common green parrot (Chrysotis festiva, Linn.) with the fat of large Siluroid fishes, and the birds thus treated become beautifully variegated with red and yellow feathers. In the Malayan archipelago, the natives of Gilolo alter in an analogous manner the colours of another parrot, namely, the Lorius garrulus, Linn., and thus produce the Lori rajah or King-Lory. These parrots in the Malay Islands and South America, when fed by the natives on natural vegetable food, such as rice and plantains, retain their proper colours. Mr. Wallace has, also, recorded a still more singular fact. 'The Indians (of S. America) have a curious art by which they change the colours of the feathers of many birds. They pluck out those from the part they wish to paint, and inoculate the fresh wound with the milky secretion from the skin of a small toad. The feathers grow of a brilliant yellow colour, and on being plucked out, it is said, grow again of the same colour without any fresh operation'". See Darwin, C. 1868. The variation of animals and plants under domestication. Vol. 2. London: John Murray [p. 280]. Darwin cites for the quotation from Wallace about poison from frogs being used to change feather colour: Wallace, A. R. 1853. Narrative of Travels on the Amazon and Rio Negro, With an Account of the Native Tribes, and Observations on the Climate, Geology, and Natural History of the Amazon Valley. London: Reeve & Co. [p. 294].

Please cite as “WCP4079,” in Beccaloni, G. W. (ed.), Ɛpsilon: The Alfred Russel Wallace Collection accessed on 7 June 2023, https://epsilon.ac.uk/view/wallace/letters/WCP4079