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.

Asks for any authentic cases of "sports", which CD calls "bud-variations". Flowers introduced from warmer temperate regions are said to be particularly apt to sport in this way.

CD now has proof that Cinchona is dimorphic and that some dimorphic plants are absolutely sterile with their own-form pollen.

Asks GHKT to examine or send pollen specimens of two Ceylon genera.

Asa Gray will try to get HWB’s paper reviewed.

Also mentions that he (CD) wrote a short review of it for Natural History Review [Collected papers 2: 87–92].

Asks whether bees or Lepidoptera visit flowers of Melastomataceae.

Congratulations on marriage, which CD considers the best and only chance for happiness in this world.

Glad HWB is near completion of book.

Begs him to thank Wallace for Melastoma information; CD "cannot endure being beaten by a beggarly flower".

CD relates Asa Gray’s pleasure over HWB’s paper and Gray’s plans to write abstract [Am. J. Sci. 2d ser. 36 (1863): 285–90].

Sends two spikes of Corydalis.

Admits he may have drawn false inference from MTM’s division of peloria into two classes.

Has finished vol. 1 [of Naturalist on the river Amazons]. CD praises book as "best ever published in England".

The review in the Athenæum was cold, as always, and insolent.

After finishing vol. 2 [of Naturalist on the river Amazons], CD still has only praise. Remarks that his family is also enjoying the book. He regrets having finished, since he so enjoyed the descriptions.

Determined to make GRW a geologist. Sends copy of C. Lyell [?Elements of geology (1838)].

Offers letters to Eliza Meteyard for her book [The life of Josiah Wedgwood (1865–6)].

Inquires about body of Porto Santo rabbit which has not arrived.

Asks for information he needs for the German translation [of Coral reefs], including correct titles of reference books and the name of a voyager.

Asks for a letter on the tameness of deer, written by Commander A. Boutakoff to R. I. Murchison and printed in the Journal [J. R. Geogr. Soc. 23 (1853): 93–101].

Would like tabulation of horned beetles if not too troublesome, but would easily settle for general remarks.

On the subject of other species mocking Heliconidae, asks whether full-coloured ones were mocked. Expresses full belief in HWB’s theory.

Encloses a copy of A. R. Wallace’s letter to the Field requesting observations on which caterpillars birds devour.

CD in utter confusion about differences between J. O. Westwood and HWB on division of certain insects. Asks if HWB will homologise certain families for him, telling him which terms would be most generally understood.

Asks also about differences on sound-producing organs of Achetidae Gryllidae.

Requests information on the standard of beauty of savages and on whether the female has any influence in selecting a male.

CD has questions related to colour differences in the sexes of butterflies, especially in relation to HWB’s paper ["On variation in sexes of Argynnis diana", Proc. Entomol. Soc. Philadelphia 4 (1865): 204–7].

Mentions that his MS on Lepidoptera [for Descent] is longer than he intended and the information is four-fifths owed to HWB.

Thanks HWB for answering questions.

The MS on Lepidoptera is almost finished and he is glad HWB will read it; he is fearful of mistakes, not being familiar with the subject.