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Darwin Correspondence Project

From Alexander Wallace   15 July [1869]1

Trinity House, | Colchester.

July 15

Dear Sir

In reply I send the following2

Yrs truly. | A Wallace.


Bombyx Pernyi3 sent to me from N. China in the cocoon   347 moths emerged

Of which 123 were ♀ & 224 ♂: out of about 4000 cocoons.

In 1868, of 46 Yama Mai4 cocoons which emerged, 25 were ♂ & 21 ♀

in 1869, of 52 Yama Mai cocoons

27 ♂ & 25 were ♀

these are all I have at your disposal5


CD annotations

4.1 Pernyi] underl pencil; ‘?’ added pencil
6.1 Yama Mai] underl pencil


The year is established by the last year given for the emergence of the moths.
CD’s query to Wallace has not been found.
Bombyx pernyi is now Antheraea pernyi, the Chinese oak silk-moth.
Bombyx yamamai is now Antheraea yamamai, the Japanese oak silk-moth.
CD published Wallace’s results in Descent 1: 313.


Descent: The descent of man, and selection in relation to sex. By Charles Darwin. 2 vols. London: John Murray. 1871.


Gives information on the proportions of sexes of certain moths. [See Descent 1: 313.]

Letter details

Letter no.
Alexander Wallace
Charles Robert Darwin
Sent from
Source of text
DAR 86: A98
Physical description
1p †

Please cite as

Darwin Correspondence Project, “Letter no. 6829,” accessed on 16 November 2019,

Also published in The Correspondence of Charles Darwin, vol. 17