Many of EB’s remarks about Origin [4th ed. (1866)] are new to CD.

Thinks of writing a short essay on man.

Struck by EB’s remarks about orang. They are similar to Carl Vogt’s remarks on origin of man from distinct ape families.

Thinks similarity of orang to Malay must be accidental.

Will send Variation when it is published.

Thanks PR for his memoir on Epipogium ["Über den Blüthenbau von Epipogium" (1866)]. The structure and manner of fertilisation are new to CD;

he has long suspected that the classification of orchids requires considerable modification.

Asks why caterpillars are sometimes beautifully coloured. It poses a problem for view that sexual selection is the explanation of colours of male butterflies.

More on mimetic butterflies.

Discusses sexual and seasonal differences in the plumage of birds and coats of mammals.

Remarks upon variations in the form of the canine tooth between the sexes in mammalian groups.

Plumage of allied species of plover.

Asks CD’s help with work on unimproved domestic animals.

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

Sexual differences in bird species and seasonal variation in plumage.

Sends a copy [missing] of a lecture by L. Agassiz on glaciers.

Claims worker wasps can generate additional workers in the absence of the fertile female.

Vladimir Kovalevsky wishes to translate Variation into Russian. He offers £1 per advance sheet.

ARW’s explanation of protective value of conspicuous coloration is ingenious.

CD still holds to sexual selection with respect to beauty in male butterflies.

Sexual selection and the races of man.

Expression of emotions is another subject he plans to include in his essay [Descent].

Asks ARW to suggest an observer in Malay Archipelago to whom he might send queries [on expression].

Asks JvH’s assistance in making observations on the expression of emotions. Encloses 17 queries that are being sent to various parts of the world.

CD’s queries on expression as reprinted in Notes and Queries on China and Japan 1 (1867): 105.

Encloses his queries about expression which he asks JPMW to forward to trustworthy observers who associate with Hottentots and Kaffirs.

Sends his [MS] questionnaire on expression and asks FvM’s help in obtaining answers based on observations of aborigines living in the interior of Australia.

Male dotterels take care of young and are less brilliantly coloured than females.

Discussion of origin of domestic sheep races. Some comments on the yak and the wild ancestors of the llama and alpaca.

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.

He has promised Mark [coachman to R. W. Darwin and Susan] that CD will continue the payment of £20 a year after EAD’s death; the house is rent free.

Reports observations on fertility of orchids he has self-pollinated and crossed with pollen of other species.

Thanks for information about the dotterel.

CD had ascertained by dissection that the female of the carrion-hawk of the Falkland Islands is very much brighter coloured than the male. Has inquired about its nidification. Mentions other instances of female birds that are brighter and more beautiful than the males and suggests causes for this anomaly.

Much obliged for lecture [On some defects in public school education (1867)]. Would leave classics to those with zeal and taste for appreciation. Learned nothing at school except by reading and experimenting in chemistry.