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Darwin Correspondence Project


From Benjamin Dann Walsh   1 March 1865

Rock Island, Illinois U.S.

March 1. 1865

My dear Mr. Darwin,

Your letter of Dec. 4 enclosing your photograph came duly to hand & by the same mail your second letter enclosing Westwood’s photograph.1 I am under great obligations to you for both. Westwood I never saw, but I have a very distinct recollection of your countenance when you were at Christ’s, & if you were to shave clean & put on a wig, I should say you are but very little changed since then.2 Immediately on the receipt of your letters, I wrote to several of my Eastern Correspondents on Westwood’s affair of the Portraits,3 & as soon as I received answers, I took occasion to write to him & communicate the results. I suppose it will probably be some little time yet before I receive a reply. There is a good portrait of Say4 in existence, of which he can have a copy taken, if he desires it. Of Harris there is nothing but a photograph extant, which I rather wonder at, considering that the New England naturalists set great store by him & are apt to get wrathy if one picks any holes in his jacket.5

I received your very interesting Paper on Trimorphism in Lythrum salicaria &c,6 & read it several times with renewed attention. I was much struck with one fact, which I should not have anticipated, viz. that in the same genus some species are trimorphic, some dimorphic & some monomorphic.7 Hence we may infer analogically that in Cynips some species may be dimorphic, & some monomorphic,8 though in Apis, Vespa & Bombus all the known species are dimorphic. I think there is some great mystery concealed in this matter, which time & patient observation & experiment will be certain to elucidate. I wish, if you have one, you would send me a copy of your Paper on Primula. 9 I saw long ago an abstract with very full extracts of your Linum paper in Silliman’s Journal.10 I quite agree with you in your note (p. 101)11 on the irrelevancy of von Mohl’s arguments.12 How can men be so muddle-headed? Has Leersia oryzoides ever been observed in a state of nature?13 If not, I do not think that we can argue conclusively from the habits of a tame organism to the habits of a wild organism. At this rate, because birds of prey will not procreate in confinement, we might infer that they never procreate in a state of nature, & consequently that eagles, like donkeys, must be immortal.

I sent you a month or two ago a Paper of mine on “Phytophagic Species”, & by this mail I send you another on “Willow-galls”.14 You will begin to think that I spawn a pamphlet bi-monthly. But with me the winter is the time for writing, & in the summer I am out in the woods reading the great Book of Nature. There is one matter in this last pamphlet which I should like your opinion on, i.e. Wagner’s procreative larvæ (pp. 571–4 & 641–4).15 The more I turn the thing over in my mind, the more I don’t believe a word of it. And yet I find that Sieboldt has to a certain extent endorsed the theory, by translating from the Danish a Paper on the subject.16 All these men seem to me to have confounded two very different things, 1st the case of alternate generation where A produces B, & B produces A & so on ad infinitum & 2nd the (supposed) case of Cecidomyia, where, in the same species, A (the larva) sometimes produces A (the larva) & then dies, & sometimes produces nothing at all but becomes gradually developed into the imago B, which reproduces A & so on. Is there anything analogous to this in the known metagenetic transformations?17 It strikes me like the theory of the schoolboy that sometimes the earth travelled round the sun & sometimes the sun travelled round the earth. But out here in the backwoods we know but very little on these great modern discoveries. I wish you would enlighten me.

I am delighted to find that you approve of the way in which I handled Agassiz.18 I am told there is a notice of that Chapter in the London “Reader” of Dec 31, but have not seen the article.19 Thank you for getting my Cynipidous theory noticed in the Nat. Hist. Review.20 There has also appeared a short notice of that Paper in the Stettin “Zeitung”, or whatever the German title of their Natural History Journal may be;21 so it will get tolerably well ventilated, at all events, which is all I wish or expect. Magna est veritas et prævalebit,22 as you by this time see with your great Theory. I told young Agassiz, who argued against your theory because so many naturalists disbelieved it,23 that the wonder was, not that so many disbelieved but that in six years from the date of its promulgation so many believed; & I asked him how many naturalists believed in Cuvier’s great theory six years after that was promulgated?24

Since I last wrote, I have read carefully through Agassiz’s “Classification”, which one of the New England Naturalists told me contained a most unanswerable refutation of Darwinism,25 though he allowed that the argument in the “Methods of Study” was a complete failure.26 The book bears neither title-page nor date, & so far from finding any refutation of your theory in it, I actually feel uncertain whether it was written & printed before or after your book was published. The line of argument is precisely the same as that in the “Methods of Study”, & one book is nothing but an abridged re-hash of the other. I was astonished to find that he believes that the same identical species can be & has been created twice over in two separate localities & in two separate geological epochs. Does any other naturalist believe this absurdity? I should have thought that in that case the theory of Chances might have taught him, that we should be as likely to find recent species in the Devonian as in the Pliocene strata, & that we might expect to meet with as many European species in Australia as in North America. He gives me the impression all the time of a dishonest lawyer pettifogging a hard case. Sometimes he won’t have it that there are any identical species in successive geological epochs— this was what he asserted roundly in a Lecture which he delivered last year in Rock Island,27 & what he asserts by implication in the “Methods of Study” & sometimes he says that there are identical species in two distinct geological epochs, but that there was a separate creation for each batch. This reminds one of the Western lawyer, whose client was sued for a kettle which he had borrowed & returned with a large crack in it, & who put in three pleas:—1st. that his client had never borrowed the kettle, 2nd. that it was already cracked when he borrowed it, & 3rd. that it was perfectly sound when he returned it.

I was also much amused to find how he & I, from exactly the same premises, arrive at very opposite conclusions. Because animals have every mental faculty that Man has, only developed in a less degree, I draw the conclusion that neither men nor animals have any souls, & he draws the conclusion that both men & animals have got souls, which can & will exist in a future elysium independently of their bodies.28 In that case, if we calculate up all the animals that have ever existed since the old Paleozoic times, the Agassizian elysium will have to be a pretty large one to hold all their souls. His idea of the soul of a Naturalist studying the souls of his favorite groups of animals—I suppose Agassiz will devote himself to the souls of Turtles & Fish—reminded me of a French parody of Virgil, which represented the soul of a Coachman in the Elysian shades busily cleaning the soul of a Coach with the soul of a brush.29

I have no possible chance out in this uncivilized region to get a sight of Bates’s Paper on mimetic Lepidoptera;30 when you see him, I wish you would tell him from me that I should be much obliged by anything from his pen. I have seen a review of his Book on the Amazonian insects in Silliman’s Journal a year or two ago,31 & was much interested in it.

I do not think that species of Bombus or of any other genus would copulate differently from their congeners; this would be a violation of what I have called the “Unity of Habits” in the same genus.32 But I have recently verified in a great many species of Bombus the well-known fact, that the ♂ reproductive organs are invariable & differ remarkably in each, just as they do in the Dragon-flies, some being simple curved hooks, & in others the hooks being armed with one or more internal teeth, the thing aimed at being evidently to keep fast hold of the anus of the ♀ by the forceps. My idea is, that a slight variation in the shape of this forceps might be better suited to encite the passions of the ♀ & so be an advantage to the ♂. No ♀ Bombus can ever be ravished, nor indeed can any other ♀ insect that I know of. Before copulation can take place, the ♀ must direct her anus upwards, just as a ♀ cat does when she is rutting. But enough of this.

I have recently been working on a large Collection of Insects from the Rocky Mountains & have partially verified a fact which has been asserted by our best N.A. Coleopterist, Dr. J. L. LeConte, viz. that a very large number of genera of Coleoptera, which in the Atlantic States are uniformly winged, contain many wingless species on the Pacific seaboard, or rather in the whole region of country west of the Great American Desert which borders the eastern base of the Rocky Mountains.33 Taken in connection with Woollaston’s facts on the prevalence of apterous types in Coleoptera on the Madeira Islands,34 & the further fact, which I have quoted on LeConte’s authority in my “N. E. Naturalists” Paper, that the Coleopterous Faunas in California &c are exceedingly limited in that geographical extent,35 does not this seem to indicate that at no very remote period, geologically speaking, this whole region of country was an Archipelago, like the Pacific Islands for example? I am going to get LeConte to enquire of Schaum & LaCordaire36 & other European Coleopterists, whether Woollaston’s facts, which I learnt from your book, are met with in other groups of Islands whose coleopterous fauna has been studied.37 It is most remarkable how apterous genera, such as Eleodes the American representative of Blaps, which are scarcely at all represented on this side of the Great Desert, swarm both in individuals & in species when you get on the other side of it. Every body has noticed this. Even families which almost everywhere else are uniformly winged, contain here certain anomalous genera which are not only wingless but have the elytra soldered together. In the long-horned beetles, there is Say’s genus Moneilema, which looks for all the world like an Eleodes, & I believe that LeConte’s genus Amphizoa is nothing but the American representative of your Hydradephagous genus Pelobius with its elytra connate & its wings gone. Lacordaire refers it to Dytiscidæ; Schaum to Carabidæ; & LeConte makes it the type of a new family.38 Its habits are at present unknown; but I feel confident that it is aquatic from the details of its structure.

Ever yours very truly | Benj. D. Walsh

P.S. I was glad to see the other day that you have the R.S. medal.39

CD annotations

2.1 I received … immortal. 2.16] ‘Unity of Coloration’ added 40
2.8 I wish … Primula. 2.9] cross in margin
2.10 I quite … arguments. 2.11] double scored
9.3 viz.... Mountains. 9.7] double scored


See Correspondence vol. 12, letters to B. D. Walsh, 4 December [1864] and [4 December 1864?]. Walsh had requested photographs of CD and John Obadiah Westwood (see Correspondence vol. 12, letter from B. D. Walsh, 7 November 1864). The photograph of CD, taken by William Erasmus Darwin, is reproduced as the frontispiece to Correspondence vol. 12; see also letter from W. E. Darwin, [19 May 1864].
Walsh was a student at Trinity College, Cambridge, when CD was at Christ’s College from 1828 to 1831 (Alum. Cantab.; see also Correspondence vol. 12, letter from B. D. Walsh, 29 April – 19 May 1864 and nn. 1 and 3).
See Correspondence vol. 12, letter from J. O. Westwood, 2 December 1864. CD enclosed Westwood’s letter, which requested portraits of Walsh, Thomas Say, Thaddeus William Harris, and ‘any other brother Entomologist of the New World’, in his letter to B. D. Walsh, [4 December 1864?] (Correspondence vol. 12).
Thomas Say.
Thaddeus William Harris was the author of an influential report on the insects of Massachusetts (Harris 1841), and had been a leading figure in economic entomology in the United States (DAB).
‘Three forms of Lythrum salicaria’. Walsh’s name appears on CD’s presentation list for this paper (see Correspondence vol. 12, Appendix III).
See ‘Three forms of Lythrum salicaria’, pp. 189–91 (Collected papers 2: 123–5). CD noted that L. graefferi was trimorphic, like L. salicaria, and that L. thymifolia was dimorphic, while L. hyssopifolia had only one form.
Walsh published a paper on dimorphism in Cynips, a genus of gall-wasps, in March 1864 (Walsh 1864a). See also n. 20, below.
‘Dimorphic condition in Primula’.
Extracts from CD’s paper ‘Two forms in species of Linum’, with a commentary by Asa Gray, were published in the September 1863 issue of the American Journal of Science and Arts, pp. 279–84; see Correspondence vol. 11, letter from Asa Gray, 7 July 1863. The journal was known as ‘Silliman’s Journal’ after its founder and first editor, Benjamin Silliman.
Walsh refers to the footnote on pp. 191–2 of ‘Three forms of Lythrum salicaria’ (Collected papers 2: 125, 130–1), which begins with a reference to Origin 3d ed., p. 101, where CD expressed his belief that in all plant and animal reproduction distinct individuals at least occasionally cross together. See also n. 12, below.
Hugo von Mohl had argued (Mohl 1863, pp. 309, 321) that the existence of small, closed, self-fertile flowers in Viola, Oxalis, and other genera was evidence against CD’s view that no species was perpetually self-fertilised (see Origin, pp. 96–101, and Orchids, p. 359). CD argued that since these genera also produced ordinary flowers accessible to cross-pollination by insects and capable of producing seeds, Mohl’s examples did not invalidate the theory that no species is perpetually self-fertilised (see ‘Three forms of Lythrum salicaria’, pp. 191–2 n. (Collected papers 2: 125, 130–1), and Forms of flowers, pp. 314, 320–1, 330). There is a discussion of Mohl 1863 in CD’s manuscript version of ‘Three forms of Lythrum salicaria’ (DAR 27. 2: A44a–b); see also Correspondence vol. 12, letter to Asa Gray, 28 May [1864]. There is an annotated copy of Mohl 1863 in the Darwin Pamphlet Collection–CUL. For CD’s observations on the small, closed flowers (later called cleistogamic) of Viola and Oxalis, see Correspondence vols. 10–12.
In ‘Three forms of Lythrum salicaria’, p. 192 n. (Collected papers 2: 131), citing Duval-Jouve 1863 on Leersia oryzoides, CD stated that the completely enclosed flowers of this grass ‘apparently offer the best case of perpetual self-fertilization’. CD later described his observations on the cleistogamic flowers of this species, from plants collected near Reigate, Surrey, and from specimens grown in his greenhouse, in Variation 2: 91 and Forms of flowers, pp. 333–5. See also Correspondence vol. 12, letter to J. D. Hooker, 13 April [1864], and letters from William Bennett, 29 April 1864 and 25 May 1864 and n. 1. CD’s notes on this species, dated between July 1864 and July 1866, are in DAR 111: A37–40 and A58.
The first part of Walsh’s article ‘On phytophagic varieties and phytophagic species’ (Walsh 1864–5) and his article ‘On the insects, coleopterous, hymenopterous, and dipterous, inhabiting the galls of certain species of willow’ (Walsh 1864b) were published in the Proceedings of the Entomological Society of Philadelphia in November and December 1864, respectively. There are heavily annotated copies of Walsh 1864–5 and 1864b, inscribed by Walsh, in the Darwin Pamphlet Collection–CUL.
Walsh 1864b, pp. 571–4 and 641–4, discussed observations made by the Russian entomologist Nikolai Petrovich Wagner of gall midges that propagated in the larval state. Wagner had described generation in the larva of the gall midge, Miastor metraloas (family Cecidomyiidae), in a monograph published in Russian (Wagner 1862); a preliminary description, which failed to identify the species, was written in 1861 and published in German in 1863 (Wagner 1863). Walsh was at first sceptical of Wagner’s claims to have observed what later became known as paedogenesis; however, see Walsh 1866, p. 288. In CD’s copy of Walsh 1864b (Darwin Pamphlet Collection–CUL), the pages discussing Wagner’s work are lightly annotated.
Walsh refers to the German invertebrate zoologist Karl Theodor Ernst von Siebold’s partial translation and discussion (Siebold trans. 1864) of Frederik Vilhelm August Meinert’s article on reproduction in insect larvae (Meinert 1864). Meinert confirmed Wagner’s observations of reproduction in the larva of Miastor metraloas. Siebold had also written an editorial note to Wagner 1863, pp. 513–14, stating that Wagner’s observations had been confirmed by others.
Walsh refers firstly to alternation of generations and secondly to Wagner’s observations of reproduction in Cecidomyia, which included larvae being reproduced asexually within the body of a parent larva (see n. 15, above). Wagner’s observations of paedogenesis were subsequently confirmed by others (see EB 13: 429, and letter to B. D. Walsh, 19 December [1865]). In the nineteenth century the term metagenesis, or alternation of generations, was sometimes also applied to ‘certain metamorphoses not now recognized as instances of alternation of generations’ (OED).
See Correspondence vol. 12, letter to B. D. Walsh, 4 December [1864]. In Walsh 1864c Walsh had criticised Louis Agassiz’s statement that the insects of the temperate zone of North America differed ‘specifically throughout’ from those of Europe, a view based on his belief in the theory of many contemporaneous local creations (see J. L. R. Agassiz 1850, pp. 187 n., 248). Walsh argued that scientific opinion was against Agassiz in that the majority accepted that identical forms existed in North America and Europe; he also argued that the similarities between the insects of the two continents were best explained in terms of genetic links (Walsh 1864c, pp. 218–23), and criticised Agassiz’s attempts to refute CD’s theory of the origin of species in his book, Methods of study in natural history (J. L. R. Agassiz 1863). There are annotated copies of J. L. R. Agassiz 1850 and J. L. R. Agassiz 1863 in the Darwin Library–CUL and the Darwin Library–Down, respectively (see Marginalia 1: 11–13), and an annotated copy of Walsh 1864c in the Darwin Pamphlet Collection–CUL. See also letter from Asa Gray, 17 January 1865 and n. 6.
The article, ‘Mr. Walsh on Darwinism’, appeared in the Reader, 31 December 1864, p. 837. The article favourably reviewed Walsh 1864c, quoting from it at length, including Walsh’s view that Agassiz had ‘totally misapprehended and misstated the Darwinian Theory, and appears never even to have given himself the trouble to read Darwin’s book through’ (Walsh 1864c, p. 223). See also n. 18, above.
CD had given Walsh’s paper on dimorphism in Cynips (Walsh 1864a) to John Lubbock, who reviewed it in the January 1865 issue of the Natural History Review, pp. 138–41 (see Correspondence vol. 12, letter from B. D. Walsh, 29 April [– 19 May] 1864, letter to B. D. Walsh, 21 October [1864], and letter from John Lubbock, 3 November 1864). There is an annotated copy of Walsh 1864a, inscribed by Walsh, in the Darwin Pamphlet Collection–CUL.
The reference is to ‘Ueber den wahrscheinlicher Dimorphismus der Cynipiden-Weibchen’, which appeared in the October–December 1864 issue of Entomologische Zeitung, the journal of the entomological society of Stettin (Osten-Sacken 1864).
Magna est veritas et praevalebit: ‘truth is great and will prevail’ (Chambers).
Alexander Agassiz had entered into correspondence with Walsh on Darwinism following the publication of Walsh 1864c (see Correspondence vol. 12, letter from B. D. Walsh, 7 November 1864); for a discussion of Agassiz’s views on CD’s theory, see G. R. Agassiz ed. 1913, pp. 47–52, and Winsor 1991, pp. 147–54.
Walsh refers to Georges Cuvier’s formulation of functional anatomy, which held that every organism represents an integrated system in which all parts mutually correspond and are adjusted to produce a definite function in relation to the organism’s environment (Cuvier 1805), a formulation which became popular after its successful application to the reconstruction of extinct vertebrates from fragments of bones and teeth (Cuvier 1812). For a discussion of Cuvier’s zoology and its reception, see Coleman 1964 and Appel 1987.
Louis Agassiz’s ‘Essay on classification’ formed part 1 of the first volume of Contributions to the natural history of the United States (J. L. R. Agassiz 1857–62); there is an annotated copy in the Darwin Library–CUL (see Marginalia 1: 9–11). The essay was reprinted as a separate book in 1858 and 1859, before the appearance of Origin, and responded to debates generated by Baden Powell’s Essays on the spirit of the inductive philosophy (Powell 1855). See Winsor 1991, pp. 6–9, 23–7. For CD’s assessment of Agassiz’s ‘Essay on classification’, see Correspondence vol. 7, letter to Asa Gray, 4 April [1858] and n. 6, and Correspondence vol. 9, letter to Cuthbert Collingwood, 14 March [1861] and n. 7.
The reference is to J. L. R. Agassiz 1863. See also nn. 18 and 19, above, and Correspondence vol. 12, letter from B. D. Walsh, 4 December [1864] and nn. 4 and 5.
Rock Island, Illinois. Louis Agassiz made a lecture tour through the American Midwest in 1864 (Lurie 1960, p. 341). See also Correspondence vol. 12, letter from B. D. Walsh, 7 November 1864.
In his ‘Essay on classification’ (J. L. R. Agassiz 1857–62, pp. 64–6), Agassiz discussed the possession of souls by animals and concluded: ‘may we not look to a spiritual concert of the combined worlds [of animals and humans] and all their inhabitants in presence of their Creator as the highest conception of paradise?’
A reference to Charles Perrault’s parody of Virgil’s Aeneid (Larousse du XXe siècle).
Bates 1861. CD recommended this paper in his letter to Walsh of 4 December [1864] (Correspondence vol. 12). CD wrote an unsigned review of Bates’s paper in the April 1863 issue of the Natural History Review, ‘Review of Bates on mimetic butterflies’. See also letter from H. W. Bates, 28 January 1865 and nn. 3–5.
Bates 1861 was reviewed by Gray in the September 1863 issue of the American Journal of Science and Arts (A. Gray 1863).
See CD’s query regarding Bombus copulation in Correspondence vol. 12, letter to B. D. Walsh, 4 December [1864]. Walsh argued that unity of habits was the ‘very essence of the thing that we call a Genus, because Habits are correlated with Structure, and Structure makes the Genus’ (Walsh 1864b, p. 570; see also ibid., pp. 641–3).
A published statement of John Lawrence Le Conte’s assertion has not been found; however, see Henshaw 1878 for a list of Le Conte’s entomological publications.
Walsh refers to Thomas Vernon Wollaston. Wollaston had stated that 200 out of 550 species of beetle inhabiting the island of Madeira were wingless or possessed a wingless habit (see T. V. Wollaston 1856, pp. 82–7). See also Origin, pp. 135–6, and n. 37, below.
On pages 220–1 of his paper ‘On certain entomological speculations of the New England school of naturalists’ (Walsh 1864c), Walsh cited Le Conte’s conclusions on the geographical distribution of Coleoptera within the United States. Parts of California, Oregon, and Washington were included in Le Conte’s western or pacific district, an area characterised as having a small number of geographically localised species of Coleoptera (Le Conte 1859, pp. iii–v). CD scored this passage in his copy of Walsh 1864c in the Darwin Pamphlet Collection–CUL.
Hermann Rudolph Schaum and Jean Théodore Lacordaire. Lacordaire was in the process of publishing a multi-volume monograph on Coleoptera (Lacordaire 1854–75).
Walsh refers to CD’s discussion of T. V. Wollaston 1856 in Origin, pp. 135–6. See also n. 34, above. CD had used Wollaston’s facts on Coleoptera on the island of Madeira in Origin as an illustration of natural selection. Arguing that individual insects with a strong tendency to use their wings would have a greater chance of being blown out to sea, whereas those with wings reduced in size or less conducive to flight would have a greater chance of survival, CD concluded that a combination of natural selection and disuse would produce wingless species over generations. See also Natural selection, pp. 291–3. CD probably discussed his theory with Wollaston in a missing letter that Wollaston received on 27 February 1855; Wollaston, however, interpreted the data in terms of adaptive use and disuse within the limits of what he thought of as an unchanging species type (see Correspondence vol. 5, letter from T. V. Wollaston, 2 March [1855] and nn. 11 and 12, and Wollaston 1856, pp. 81–7, 186–94). CD’s annotated copy of T. V. Wollaston 1856 is in the Darwin Library–CUL (see Marginalia 1: 876–9).
Say described the genus Moneilema in Say 1823–4, pp. 403–4. Le Conte described the genus Amphizoa in Le Conte 1853, pp. 227–8, and used it to represent the distinctive family Amphizoidae (see Le Conte 1861–2, pp. 36–8); Lacordaire placed Amphizoa in the family Dytiscidae, noting that the genus had a singular mixture of the characteristics of Dytiscidae and Carabidae (Lacordaire 1854–75: 1, pp. 409–410); Schaum placed it in the family Carabidae (Schaum 1860, p. 53). ‘Hydradephagous’ refers to aquatic, predatory beetles; Pelobius was a European genus of beetles in the family Dytiscidae, with a head resembling the characteristics of the Carabidae, and was described in Schönherr 1806–17, 2: 27–8.
The Royal Society’s Copley Medal was presented to CD on 30 November 1864 (see Correspondence vol. 12 and Appendix IV). The award was announced in the January 1865 issue of the American Journal of Science and Arts, p. 114.
See letter to B. D. Walsh, 27 March [1865] and n. 5.

Letter details

Letter no.
Walsh, B. D.
Darwin, C. R.
Sent from
Rock Island, Ill.
Source of text
Field Museum of Natural History, Chicago
Physical description


Sends his paper on "Willow-galls" [Proc. Entomol. Soc. Philadelphia 3 (1864): 543–644].

Lengthy criticism of Agassiz’s views on species as stated in his Essay on classification [1857].

Interested by CD’s trimorphism in Lythrum. Thinks some great mystery may lie in the fact that in some genera, some species are tri-, some di-, and some monomorphic, and in other genera, Apis, Vespa, Bombus, all the known species are dimorphic.

Please cite as

Darwin Correspondence Project, “Letter no. 4778,” accessed on 11 February 2016,