His distress that his engagement has been broken off.

Sends copies of two papers ["On the parrots of the Malayan region", Proc. Zool. Soc. Lond. (1864): 279–97;

"On the physical geography of the Malay Archipelago", J. R. Geogr. Soc. 33 (1863): 217–34].

Sends papers with comments. Convinced that the Aru pig is a species peculiar to New Guinea fauna, not a domestic animal that ran wild.

Admires CD’s paper ["Three forms of Lythrum", Collected papers 2: 106–31].

Thanks CD for paper ["Climbing plants"].

Reports case of variation becoming at once hereditary – a crested blackbird with crested young.

Information concerning improvements in the Reader under new sponsorship.

Current reading and work [on pigeons for Ibis 1 (1865): 365–400, and catalogue of his collection of birds].

Book of travels postponed indefinitely.

Looks forward to reading Variation.

Explains how two or more female forms occur in one species through selection. The physiological problem remains of how each produces offspring like the other without intermediates. Is not CD’s case of varieties that will not blend the physiological test of a species needed for "complete proof of the origin of species"?

"Travels" postponed.

Lengthy analysis of sources of misunderstanding of natural selection. Advocacy of Spencer’s term "survival of the fittest" instead of "Natural Selection". ARW urges CD to stress frequency of variations.

Thanks CD for 4th ed. of Origin.

Discusses abnormal sexual characters produced by mimicry. ARW’s papers on the subject.

Agassiz’s "marvellous" Amazonian glacier theory.

Protective role of colours in caterpillars and butterflies. Sexual differences in colours of butterflies.

ARW responds to CD’s list of queries about expression. Suggests acquiring informants through publishing the queries in newspapers. His doubts about their importance.

Has submitted caterpillar question to Entomological Society.

Describes his view on colour [of plumage] of males and females – i.e., that absence of brilliant colour in either sex is due to need for protection in incubation, rather than to sexual selection.

Never imagined that the facts about sexual selection could be new to CD. Thought fact that brightly coloured females build concealed nests and almost all those in which sexes differ remarkably build exposed nests might be new to him. Some problems remain. Sends his notes for CD to use if he wants.

CD is invited to see ARW’s collections at Bayswater.

ARW has written an answer to the Duke of Argyll and North British Review criticisms.

Informs CD of his reply to Argyll and the North British Review criticisms [in "Creation by law", Q. J. Sci. 4 (1867): 471–88]. Cites "the predicted Madagascar moth" and Angraecum sesquipedale.

Birth of Herbert Spencer Wallace.

Response to CD’s comments on "Creation by law" [see 5637].

The limits of variation discussed.

Thanks for Variation.

Reports work on his travel book [The Malay Archipelago (1869)].

Responds to CD’s queries on polygamy in birds and orang.

Discusses sexual selection and secondary characters; colours and sexual preference.

Expresses his admiration for Pangenesis; it is superior to Herbert Spencer’s theory.

ARW differs somewhat with CD’s chapter on causes of variability [ch. 22 in Variation]. Thinks several of CD’s arguments are unsound.

Briefly discusses how natural selection might aid in producing sterility between allied species.

Offers enclosure demonstrating that natural selection could produce sterility of hybrids.

More on Pangenesis and the inadequacy of H. Spencer’s approach.

Pleased that CD approves his idea about caterpillars.

Thinks CD is right about selection in butterflies, but still believes protective adaptation has kept down colours of females.

Cannot yet see action of natural selection in forming the races of man.

On critical exchanges at the Linnean Society on natural selection and mimicry.

Roland Trimen’s paper on South African mimetic butterflies ["On some remarkable mimetic resemblances among African butterflies", Trans. Linn. Soc. Lond. 26 (1870): 497–523; read 5 Mar 1868].

Coloration of butterflies; brilliantly coloured females.

Commends CD on his paper on specific differences in Primula [J. Proc. Linn. Soc. Lond. (Bot.) 10 (1869): 437–54; reprinted and revised in Forms of flowers] as a test-case proving origin of real species.