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.

Gratified by CD’s approval of paper which was also praised by Hooker and Wallace. Only cares for one other opinion, that of C. Felder of Vienna. He finds ordinary entomologists are not scientific men. Asks for more criticisms; desires to publish paper in a widely circulating journal to advertise his book.

[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.

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.

Has sent copy of his paper to Asa Gray.

Melastomad flowers are strikingly neglected by pollinators.

Murray has ordered many illustrations for HWB’s Naturalist on the river Amazons.

Wallace noticed that melastomads in Malay archipelago were visited by small Hymenoptera.

Darwinism discussed at the last meeting of the Zoological Society. The Darwinians had the best of it.

HWB has committed the "folly" of marriage [to Sarah Ann Mason, 15 Jan 1863].

Printing of vol. 1 [of Naturalist on the river Amazons] is nearly finished.

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].

Preparations under way to move to London account for delay in thanking CD for his review [Collected papers 2: 87–92].

His book is finished, and he is sending a copy to CD; owing to the great expense few copies will be sent to reviewers.

Thanks HWB for his book [Naturalist on the river Amazons]. Feels sure it will often be alluded to in other works.

Asa Gray is fascinated by the "Butterfly paper" ["Contributions to an insect fauna of the Amazon valley", Trans. Linn. Soc. Lond. 23 (1862): 495–566].

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.

Expresses hope that CD is ready to pronounce sentence on his book;

he relates his financial position and mentions that he hopes to get a position at the British Museum.

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.

His satisfaction at CD’s acceptance of book as well as total public acceptance. Murray has given him a £250 advance. His pleasure at Asa Gray’s words.

Next task will be to write on origin [of species] by segregation of local races.

HWB’s concern over CD’s poor health.

Gives accounts of reviews of his book in the Times and in the Revue des Deux-Mondes by E.-D. Forgues ["Un naturaliste sous l’équateur", Rev. Deux-Mondes 46 (1863): 703–37].

Thanks CD for the A. Gray review of his paper [see 4022].

Reports his current work is a monograph on Mantidae.

Returns Gray’s review [of paper on mimetic analogy, Am. J. Sci. 2d ser. 36 (1863): 285–90]

and expresses his sorrow over CD’s health.

Pleased at receiving CD’s letter.

HWB informs him of favourable notice of the mimetic paper [in Wiegmann’s Arch. Naturgesch. 29 (1863) pt 2: 315–19].

He is pleased with his post [Asst. Sec. of Royal Geographical Society].

Expresses pleasure at signs of CD’s recovery.

HWB’s work on the identification of species of the genus Colobthea; relates the large number of modifications that occur in the sexual organs of closely allied species. Does not doubt that this contributes greatly to multiplication of species in nature.

He encloses a portrait and asks for one of CD.

He has sent mimetic paper to B. D. Walsh.

Mentions work at Royal Geographical Society on N. Pole business [plans for an Arctic expedition, eventually postponed until 1875–6].