My dear Sir

I will send you in a few days a copy of a new Edit. of my Orchids, as I think the account of Catasetum tridentatum is worth your reading as a striking instance of atavism accompanied by sterility.¹

I read German so slowly, and have had lately to read several other papers, so that I have as yet finished only half of your first essay and two-thirds of your second.² They have excited my interest and admiration in the highest degree, and whichever I think of last seems to me the most valuable. I never expected to see the coloured marks on caterpillars so well explained; and the case of the ocelli delights me especially.³ I think that the enclosed extract will interest you; I confess that the view formerly seemed to me fanciful, but it does so no longer.⁴

Do you know Caligo eurolochus? M^r. Butler, one of our best Lepidopterists, showed me a specimen some years ago, and said that he believed the immense ocelli on the under side of the wings, served to frighten any animal which approached the butterfly from beneath.⁵

I told M^r. Butler your views about the stripes on caterpillars; and he told me that a friend who was a good collector, shewed him a bush of Ligustrum with excrement beneath it, from which circumstance he was sure that there was a caterpillar of Sphynx ligustri living on it; but M^r. B. and his friend could neither of them find it until they searched every branch from base to top.⁶ M^r. Butler also mentioned to me the case of a caterpillar with long thin hairs, standing out laterally, which make it very difficult to be discovered as it presents no defined outline.

There is one other subject which has always seemed to me more difficult to explain than even the colours of caterpillars, and that is the colour of birds’ eggs, and I wish you would take this up.⁷

I saw two or three days ago, Sir J. Lubbock, and he expressed the liveliest interest about your book.

With my best thanks, and much respect | I remain, my dear Sir | Yours sincerely | Ch. Darwin.

P.S.— M^r. Bates tells me of a clergyman, M^r. Hallins and another gentleman who have a most beautiful, accurate and large collection of drawings of all the stages of the caterpillars of British Lepidoptera. They cannot afford to publish the collection. M^r. Bates thinks that M^r. Hebbins would lend you his share of the drawings, if they would be of interest to you to examine them, but the other man, a M^r. Buckler is bitter against evolution and probably would not lend his share, which is the larger one.⁸ Please inform me whether you think an examination of the drawings would be useful to you, and then we could try. I am going to lend your book to M^r. Bates.

C.D.