Darwin Correspondence Project

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.