Thanks for interesting letter which confirms belief that a good observer is a good theorist.

He is glad to hear that HWB, with his wide knowledge of natural history, has anticipated CD in many respects and agrees with the Origin.

Has been thoroughly attacked, especially by entomologists – J. O. Westwood, T. V. Wollaston, and Andrew Murray.

Glad HWB is writing on "equatorial refrigeration"; CD expresses his belief in north to south migration during glacial period.

Comments on the great extent of variations and on the acknowledgment of the new idea of greater female variety.

Expresses belief that the glacial period did affect the tropics, though HWB’s arguments have confounded him.

Poses a series of questions concerning sexual selection.

CD urges HWB to write on his travels;

asks for facts on domestic variations;

is pleased by HWB’s acceptance of the theory of sexual selection.

He still believes in migration from north to south during glacial age.

Hopes Bates will publish a paper on mimicry.

Recommends publisher for HWB; admires J. van Voorst but suggests Murray.

In reply to HWB’s letter [missing], comments on neuters and mimicry.

Thanks HWB for information on Volucella, although he does not know when he will use it.

Is glad HWB is beginning his book.

CD is beginning work on his orchid book.

Thanks HWB for references.

Praises his paper ["Contributions to an insect fauna of the Amazon valley", read before Linnean Society, 21 Nov 1861, Trans. Linn. Soc. Lond. 23 (1862) : 495–566] which solves "one of the most perplexing problems which could be given to solve".

Discusses the difficulties of writing and expresses disappointment at Wallace’s book [Travels on the Amazon (1861)].

Praises MS of first chapter of HWB’s book [The naturalist on the river Amazons (1863)]. Suggests he give common names and make comparisons to familiar English species to help readers. Suggests a few changes. Will speak strongly to Murray about publishing whenever HWB is ready.

Has been in bad health and has just read HWB’s MS in the last two days. Praises the book; assured it will be successful. Offers to write to Murray. Hooker interested in conclusions on colour.

Encloses note from Murray, hoping it will be satisfactory. Murray is ready to see as much of MS as possible. Murray is considered honest but may be cautious, since HWB’s name is unknown to the public.

Writes that [Murray’s] terms are very favourable; has never heard of such terms offered for a first work. HWB can depend on fact that Murray is pleased with it [The naturalist on the river Amazons].

Thanks for information on domestic animals of Indians.

Glad Murray thinks well of MS of The naturalist on the river Amazons.

CD working on proofs of Orchids.

Invitation to visit; Hooker will be present. Gives directions to Down. Also plans to invite John Lubbock over for an evening.

Thanks for letter and "valuable" extracts.

If S. American Carabi differ more from other species than do those from other distant locations (e.g., Siberia, Europe, etc.), CD agrees that difference would be too great to have occurred in the recent glacial age; CD also rejects independent origin. Plants seem to migrate more readily than animals. HWB should not underrate length of glacial period; CD also believes they will be driven to an older glacial period.

Sorry about news of British Museum – hopeless to contend against anyone supported by Owen.

CD dearly wishes HWB could find a situation in which he could give time to science.

Referring to conversation with Lyell, CD is certain that there was a Miocene glacial period.

Compliments HWB on the mimetic display at the British Museum. Those at the Museum readily accepted HWB’s "doctrine".

Was shown genital organs of closely allied Chrysomelidae.

Albert Günther is candidate for position at Museum.

Encloses a question [missing] concerning language [from Hensleigh Wedgwood].

Asks for news of HWB and his book.

There has been sickness in CD’s family; one of the boys [and Emma] had scarlet fever.

Has had a letter from Edwin Brown of Burton who is working on classification of Carabi.

Thanks for last note. Assures HWB that all writers have problems similar to his.

Plans to inquire at Linnean Society for HWB’s paper.

His family, including Mrs Darwin and Leonard, are now well.

Just finished HWB’s paper ["Contributions to an insect fauna of the Amazon valley", Trans. Linn. Soc. Lond. 23 (1862): 495–566], one of the most remarkable he has ever read. Found mimetic cases and connection of facts marvellous. Finds equally important the facts on variation and segregation of complete and semi-complete species. Questions whether insect mimicry is not due to small size and defencelessness. Criticises title of paper. Mentions that Wallace will appreciate it.

[Apparently in reply to question in missing portion of 3825.] A written agreement is unnecessary, but a letter stating terms would prevent misundertanding. He will attempt to have a review of HWB’s paper published.

Thanks for paper and references on variations [missing].

Regrets HWB’s trouble about artists, etc., saying such trouble is a law of nature.

Asks whether HWB has heard of starving Indians who are forced to cook in different ways, and eat new things.