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Darwin Correspondence Project

To J. D. Hooker   7 [April 1874]1

Down, | Beckenham, Kent.


My dear H.

Perhaps Riley may have sent you the larvæ of the Pronuba moth so as to fertilise the Yuccas. As I have no plants, I forward them by this post to you, with his brief instructions.— It is the most wonderful case of fertilisation ever published.—2 Do try them, or give them away or throw them away.

Yours affect. | C. Darwin

We have asked Dr. Klein, Günther & Ld. Monteagle here for next Sunday,— Carriage at Orpington for 4o12 Train on Saturday. Any hope of you?3


The month and year are established by the reference to a visit by Edward Emanuel Klein to Down House, and by the reference to Riley 1873 (see nn. 2 and 3, below).
Charles Valentine Riley described the pollination of Yucca, which occurs during oviposition of the yucca moth Pronuba yuccasella (now Tegiticula yuccasella), in Riley 1873. An offprint of Riley 1873 is in the Darwin Pamphlet Collection–CUL, and is annotated by CD: ‘Wonderful case of fertilisation, when the moth puts pollen on intentionally’. For more on the pollination mutualism of the yucca and yucca moth, see Pellmyr et al. 1996.
CD refers to Edward Emanuel Klein, Albert Günther, and Thomas Rice. Emma Darwin’s diary (DAR 242) records only Klein’s visit on Saturday 11 and Sunday 12 April 1874.


Riley, Charles Valentine. 1873. On the oviposition of the Yucca moth. American Naturalist 7: 619–23.


C. V. Riley’s case of Pronuba moth and the fertilisation of Yucca, is the most wonderful case of fertilisation ever published [Am. Nat. 7 (1873): 619–23].

Letter details

Letter no.
Charles Robert Darwin
Joseph Dalton Hooker
Sent from
Source of text
DAR 95: 321
Physical description
ALS 1p

Please cite as

Darwin Correspondence Project, “Letter no. 9395,” accessed on 23 May 2022,

Also published in The Correspondence of Charles Darwin, vol. 22