# From H. W. Bates   19 May 1862

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.1

I have just received the German monograph on Chilian Carabi.2 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.3 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〈  〉 〈    〉4   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, $\frac{3}{4}$ ths 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,5 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.6 It is very clear.— In Ann. Nat. Hist. for June you will see a note of mine on a new way of regarding local varieties7   I have sent in an application for British Museum. situation but it will be of little use.8 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.9 I shall call on Murray.10 Can I do anything for you. The address 43 Harwood St Hampstead road will find me.

## CD annotations

1.1 The … whole. 1.5] crossed pencil !alignleft!2.2 He concludes … Carabi?” 2.9] crossed pencil
5.1 Thanks … Bates 6.1] crossed pencil
7.1 I go … me. 7.3] crossed pencil
Top of first page: ‘Ch. IV’11 added brown crayon

## Footnotes

See letters to H. W. Bates, 4 May [1862] and 9 May [1862].
Gerstaecker 1858.
The entomologist Joseph Sugar Baly was a leading authority on phytophagous Coleoptera (Modern English biography).
Edward Westley Janson was the curator of the Entomological Society of London.
Bates’s name appears on CD’s list of presentation copies of this work (see Correspondence vol. 10, Appendix IV).
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.
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]).
Edward W. Robinson drew the coloured illustrations for Bates 1862a.
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.
CD probably refers to chapter 4 of his ‘big book’ on species, on ‘Variation under nature’.

## Summary

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

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

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

Thanks for copy of Orchids.

## Letter details

Letter no.
DCP-LETT-3564
From
Henry Walter Bates
To
Charles Robert Darwin
Sent from
Leicester
Source of text
DAR 160.1: 69
Physical description
4pp damaged †