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Darwin Correspondence Project

From B. D. Walsh   1 May 1868

Rock Island Ill.

May 1. 1868

Chas. Darwin Esq.

My dear Sir,

I have just received your letter of April 13th.. I am very glad that the few scraps of information I have been able to give you have been of some service.1

I write now because a case of apparent Sexual Selection in a genus of Butterflies has occurred to me, of which perhaps you will like to learn the details.

You probably are familiar with the common “Orange-tip Butterfly” (Anthocaris (mancipium) cardamines); & are aware that the males have a very conspicuous orange tip at the tip of the upper surface of the front wing, of which orange tip the female is entirely destitute. We have in the Atlantic States a species (Anthocaris genutia Fabr.), ranging from New York to Maryland, where the sexes differ in precisely the same manner. I have it ♂ ♀, but it is not found in Illinois.

In Anthocaris sara Boisduval (a California species) the male has just such an orange tip as the males of the other two species except that it is edged internally with black & is rather of a redlead color than orange.; but in the females it is said to be “paler than in the males, not edged with black, & divided at the extremity by a series of sulphury white marginal points.” I possess ♂; ♀ I do not personally know.2

In another California species, which is considered rare & which I do not possess in either sex, (Anthocaris lanceolata Boisd.)3 both sexes are said to be destitute of any orange or yellow or yellowish tip to the front wing. This species is only a little larger than the Atlantic species (A. genutia) & appears to be its representative. (Expanse 118 inch). A. sara is as large as A. cardamines.

There are two other N. A. species of Anthocaris. 1st. Anth. creusa Doubl. from the Rocky Mountains (Doubleday & Hewitson’s genera of Diurnal Lepidoptera, London, plate VII, fig. 1) which I know nothing about, & 2nd. Anth. ausonioides Edwards, (formerly supposed by Boisduval to be identical with the European Anth. ausonia,) from California, the Rocky Mountains & Russian America. In this species, as well as in the European ausonia, (& apparently also in the European Anth. Tagis & A. Simplonia) both sexes are destitute of any orange tip.4

In this genus, therefore, we have the following gradations, the first of which, being the most numerously represented, may be considered as the primordial or normal form;

A. Both sexes without any orange tip. Ausonia, Tagis & Simplonia (Europe); Ausonioides & lanceolata (N. A.)

B. Male only with an orange tip. Cardamines (Europe); genutia (N. A.)

C. Male with an orange-red tip; female with the tip paler. Sara (N. A.)

(Anth. creusa Doubleday (N. A) locus incertus.)

I infer that in B the orange tip has been acquired by Sexual Selection, & that in C, this peculiarity of ♂, having been very long & very firmly established, is beginning by inheritance to appear in ♀ also.5 In confirmation of this theory, it may be remarked that in Sara ♂ the orange-red tip appears on both surfaces of the front wing, whereas in genutia ♂ & (unless my memory fails me) in cardamines ♂ also, it is orange & is confined to the upper surface. Whether it is so in Sara ♀, is not quite clear from the only description I have (that of Morris);6 but I rather infer that it is not, but appears, only much paler, on the lower surface as well as on the upper surface, in that sex.

Bates, in his Paper on the Lepid. Amazon Valley, shows how by simple variation in one & the same species (Leptalis Theonöe), & belonging too to the same family as Anthocaris, the tip of the upper surface of the front wing changes gradually from white to red (p. 565. Plate LV. figs. 9, 6, 4, 8, 5, 7. Plate LVI. figs. 3, 2, 1.)7

It is remarkable, as illustrative of what I have called “Unity of Coloration”,8 how very generally in Butterflies which have the tip of the front wing prolonged in a kind of triangle, that triangular space is occupied by white or by red spots, or by spots partly red partly white. You will see this in most of the Vanessa, especially in Atalanta & cardui & several species closely allied to the latter; in Danais archippus & Berenice & in Limenitis disippus & L. artemis. But it is more especially remarkable in Libythea motya, & in an undescribed(?) species of Apatura in my collection.9

In all the above-named Anthocaris, so far as I am aware, the under surface of the hind wing is marbled in a very peculiar & characteristic manner, with more or less tendency for the marbling to separate into 2 or 3 jagged transverse bands. In the arctic or subarctic genus chionobas (Hipparchia family)10 the same surface is marbled in almost exactly the same style, except that nature paints here with brown instead of green; &, instead of being subobsolete, the jagged transverse bands are very strongly pronounced. Here we have “Colorational Unity” again.

I sent you a Copy of my “Report” a few days ago. There is scarcely anything in it that will interest you, except that I have been presumptuous enough to criticize you on pp. 65–66.11 I have been anxiously expecting your Book; but it has not yet come to hand. I wrote to Baillière long ago, to ask him to forward it to me by Express as soon as he received it.12

The “Practical Entomologist” was discontinued finally last October; but, as you will see, I have my hands full now as Acting State Entomologist, at all events until next winter.13 Entomology is rather looking upwards here in the Practical World. The State of Missouri has just appointed a young friend of mine, C. V. Riley14 of Chicago, State Entomologist with a salary of $2500 per annum. He is comparatively only a beginner in the science, but he is a hard-working intelligent young fellow, understands German which I am ashamed to say I do not, & though a very poor classical scholar like the most of his countrymen, has the stuff in him to be eventually very useful in his special line. I don’t know what is the reason, but neither France for the last hundred years, nor America since she was originally colonized, has ever produced one single good Greek Scholar.

“Darwinism” is now becoming quite a common creed in the United States, especially among the Entomologists; but I see that Agassiz15 is as inveterate as ever against it. Still, he is not ὁ πανύ now,16 as he used to be, even in New England; for several New England men have been lately led astray by the great heresiarch of Bromley.

Yours ever very truly, | Benj. D. Walsh

P.S. I mentioned in my last a horny black mark found in hind wing of our common ♂ Danais. Bates says this occurs in all ♂ Danais. (p. 502)17

CD annotations

1.1 I have … details. 2.2] crossed blue crayon
5.2 both … wing. 5.3] scored blue crayon
6.5 In this … tip. 6.7] scored blue crayon
7.4 A.... Sara (N. A.) 7.7] ‘(I must find out whether Indian Orange-tip is Anthocaris)’18 added pencil
7.14 Whether … sex. 7.16] scored blue crayon
8.1 Bates, … red 8.4] scored blue crayon
9.1 It is … (p. 502) 15.2] crossed blue crayon
11.1 I sent … received it. 11.5] ‘Gradation’ added and circled blue crayon ‘Lamellicorn stridulata | Trox’19 added pencil


Mancipium is an invalid synonym of Anthocharis (Pitkin and Jenkins 2004, accessed 16 August 2005). Anthocharis genutia is now A. midea, the falcate orangetip. Anthocharis sara is the Pacific orangetip butterfly. Walsh’s quotation is from Morris 1862, which also uses the incorrect subsequent spelling ‘Anthocaris’.
Anthocharis lanceolata, the gray marble butterfly.
Anthocharis creusa is now Euchloe creusa, the northern marble butterfly; it does not have orange tips. Anthocharis ausonioides is now E. ausonides, the large marble or creamy marblewing. Anthocharis ausonia is now E. ausonia, the dappled or pearl white. Anthocharis tagis is now E. tagis, the Portuguese dappled white, and A. simplonia is E. simplonia. Walsh refers to Doubleday and Westwood 1846–52, vol. 1; William Chapman Hewitson illustrated the work. Jean Alphonse Boisduval’s remark about A. ausonides and A. ausonia is in Boisduval 1852, p. 286. Russian America: i.e. Alaska. Alaska was sold to the United States by the Russians in 1867.
CD reported Walsh’s speculation on the colours of Anthocharis cardamines, A. genutia, and A. sara in Descent 1: 393–4. Locus incertus: place uncertain.
Walsh refers to John Gottlieb Morris and to Morris 1862. Morris describes the upper and underside of the male Anthocharis sara, but makes no such distinction in describing the markings of the female (Morris 1862, p. 21).
Walsh refers to Henry Walter Bates and to Bates 1861. Leptalis theonoe is now Dismorphia theucarila theonoe. Anthocharis and Dismorphia are both members of the family Pieridae.
According to Walsh’s law of ‘Unity of Coloration’ (Walsh 1864, pp. 635–6), identical shades of colour and patterns of design in a group of species indicated a ‘genetic connection’. See Correspondence vol. 13.
Vanessa atalanta is the red admiral, and V. cardui the painted lady butterfly. Danais archippus is now Danaus plexippus (the monarch butterfly); Danais berenice is now Danaus gilippus berenice (the queen butterfly). Limenitis disippus is now L. archippus (the viceroy butterfly), and L. artemis is L. arthemis (the red-spotted purple). Libythea motya is now Libytheana motya (the Cuban snout butterfly).
Chionobas is a synonym of Oeneis; Chionobas was in the family Satyridae (Morris 1862), and is now in the family Nymphalidae, subfamily Satyrinae. Hipparchia is a closely related genus of Satyrinae.
Walsh refers to his ‘First annual report on the noxious insects of Illinois’ (Walsh 1867b). There is an annotated offprint in the Darwin Pamphlet Collection–CUL. On page 65, Walsh argued that a form of the plum Curculio moth that fed not on peaches and plums but on butternuts and walnuts was a different species, since it did not interbreed with the other form; he added: In the recent much enlarged and improved edition of the ‘Origin of Species’, Mr. Darwin has quoted with general approbation my views upon this very interesting subject, but has incidentally remarked that I am ‘forced to assume that those forms which have lost the capacity for intercrossing should be called species’. (Fourth English edition, pp. 55–6.) This, I think, can scarcely be called an assumption. It is a definition. CD annotated the back cover of the offprint: ‘p. 65 criticism on me, just)’. In Origin 5th ed., p. 56, CD revised this passage.
Walsh refers to Variation; he had books sent to him by the French publisher Baillière, who had offices in London and New York. Walsh was on CD’s presentation list for Variation (see Correspondence vol.16, Appendix IV).
Walsh became western editor for the Practical Entomologist, a publication sponsored by the Entomological Society of Philadelphia, in 1865, and editor-in-chief in 1866 (ANB; see also Correspondence vol. 14, letter from B. D. Walsh, [28 November 1866]). He was appointed Illinois State entomologist in 1867 (ANB).
ὁ πανύ Agassiz: the real, or the famous Agassiz.
After his citation of Walsh’s remarks on Anthocharis in Descent 1: 393, CD mentioned an ‘allied Indian form, the Iphias glaucippe’, in which the orange wing-tips were fully developed in both sexes. CD evidently consulted Alfred Russel Wallace about the name (see CD’s note in DAR 81: 140). Iphias glaucippe is a synonym of Hebomoia glaucippe.
CD asked Walsh about Trox in his letter of 9 June 1868.


ANB: American national biography. Edited by John A. Garraty and Mark C. Carnes. 24 vols. and supplement. New York and Oxford: Oxford University Press. 1999–2002.

Bates, Henry Walter. 1861. Contributions to an insect fauna of the Amazon valley. Lepidoptera: Heliconidæ. [Read 21 November 1861.] Transactions of the Linnean Society of London 23 (1860–2): 495–566.

Boisduval, Jean Alphonse. 1852. Lépidoptères de la Californie. [Read 25 February 1852.] Annales de la Société entomologique de France 2d ser. 10: 275–324.

Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 28 vols to date. Cambridge: Cambridge University Press. 1985–.

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

Morris, John Gottlieb. 1862. Synopsis of the described Lepidoptera of North America. Part 1: diurnal and crepuscular Lepidoptera. Smithsonian Miscellaneous Collections, vol. 4. Washington, D.C.: Smithsonian Institution.

Origin 5th ed.: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. 5th edition, with additions and corrections. By Charles Darwin. London: John Murray. 1869.

Variation: The variation of animals and plants under domestication. By Charles Darwin. 2 vols. London: John Murray. 1868.


BDW believes the coloration of species [of Anthocaris] provides a case of sexual selection.

The state of entomology in the U. S.; Darwinism now a common creed, especially among entomologists.

Letter details

Letter no.
Benjamin Dann Walsh
Charles Robert Darwin
Sent from
Rock Island, Ill.
Source of text
DAR 82: A115–16
Physical description
ALS 4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 6156,” accessed on 26 June 2022,

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