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Letter 3564

Bates, H. W. to Darwin, C. R.

19 May 1862

    Summary Add

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    Miocene glacial period a remarkable discovery; if it is true, enlargement of Tertiary period necessary.

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    Received German monograph on Chilean Carabi that does not answer where isolated species came from.

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    HWB finds genital modifications of Chrysomela strong support for the theory.

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    Thanks for copy of Orchids.


King St Leicester

19 May /62

My Dear Mr Darwin

The discovery of signs of a glacial period in Miocene times is very remarkable as I dare say you have thought, in as much as the whole tertiary <ep>och has been always considered a time of greater warmth than the present in the Northern Hemisphere. But if it turns out a cold epoch intervened in middle of the tertiary it would only compel us to enlarge the lapse of time allowed to the whole.

I have just received the German monograph on Chilian Carabi. It is very complete. The author is of high reputation. He concludes that the 11 species form only a section of the genus although very closely allied amongst themselves & distinct as a body from all Carabi of the Northern Hemisphere. He anticipates no future discovery to modify <current> conclusions on the Geographical distribution of the genus. No Carabus has been found within the tropics & none beyond the Southern tropic in Eastern Hemisphere   He goes into many inquiries arising out of the subject but strange to say does not start the question ``Whence came these isolated Chilian Carabi?''

I never thought of modifications in horny genital apparatus of closely-allied Chrysomelæ being a difficulty <for the> theory. Quite the contrary it see<ms that> they were a strong support of it. Mr <Baly> has found that an English Chr<ysomela> believed on other grounds to be a <    > in these organs from its supp<  > <    >   He therefore again separates it & <there> is an end of the matter. Like many other <natur>alists who aim only at separating species neatly in their collections & monographs, Mr Baly never thinks of the possibility of gradual modification & consequently never looks in Nature for it. I believe, as regards the total specific form, 34ths of the species in all large groups will be found, when specimens are collected over a wide area, to be incapable of sharp definition from their nearest allies.

<    > modifications have scarcely ever been <called for>, even in the whole specific char<acter or> special organs. Mr Janson, an <entom>ologist tells me there is a difference <in genital> apparatus between two English <Carabi> C. hybrida & C. maritima. Now <modern> <en>tomologists, on the most conclusive <evidenc>e have re-united these two. It appears <h>owever the two are more distinct in England than on the Continent! This is what I should expect from observations on S. American insects. There is a gradual divergence amongst varieties of a species over a wide area. Who would think of examining the genital apparatus through all the graduated series of vars. of these Cicindelæ?

Thanks for the copy of ``Orchids''. I have read it through with great pleasure. It is very clear.— In Ann. Nat. Hist. for June you will see a note of mine on a new way of regarding local varieties   I have sent in an application for British Museum. situation but it will be of little use. Something else may turn up soon

Yours sincerely   H W Bates

I go tomorrow to London, for three days chiefly to see the artist about finishing the plates for Linnean Transactions. I shall call on Murray. Can I do anything for you. The address 43 Harwood St Hampstead road will find me.

    Footnotes Add

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    f1 3564.f1
    See letters to H. W. Bates, 4 May [1862] and 9 May [1862].
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    f2 3564.f2
    Gerstaecker 1858.
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    f3 3564.f3
    See letter to H. W. Bates, 9 May [1862] and n. 5.
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    f4 3564.f4
    The entomologist Joseph Sugar Baly was a leading authority on phytophagous Coleoptera (Modern English biography).
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    f5 3564.f5
    Edward Westley Janson was the curator of the Entomological Society of London.
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    f6 3564.f6
    Bates's name appears on CD's list of presentation copies of this work (see Correspondence vol. 10, Appendix IV).
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    f7 3564.f7
    Bates refers to the final section of Bates 1862b. In ibid., p. 451, having described some local varieties of Anisocerus onca, Bates stated: It is the custom of naturalists, when they subordinate varieties to a species, to fix upon one of the forms as the original, to which the rest are referred: this original is generally the one first described or best known … but, strictly speaking, no form can be said to be a variety of another existing form unless it can be proved or shown to be highly probable that the one descended from the other, this other itself remaining meanwhile unchanged.
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    f8 3564.f8
    The reference is to an assistantship in the department of zoology at the British Museum (see letter from H. W. Bates, 30 April 1862, and letters to H. W. Bates, 4 May [1862] and 9 May [1862]).
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    f9 3564.f9
    Edward W. Robinson drew the coloured illustrations for Bates 1862a.
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    f10 3564.f10
    John Murray was to publish Bates's account of his travels in Brazil (Bates 1863). See the letters to H. W. Bates, 31 January [1862] and 27 [February 1862] concerning Bates's arrangement with Murray.
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    f11 3564.f11
    CD probably refers to chapter 4 of his `big book' on species, on `Variation under nature'.
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