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Darwin Correspondence Project

To Arthur Rawson   6 June [1863]1

Down. | Bromley. | Kent. S.E.

June 6

Dear Sir

I am very much obliged to you for your kindness in sending me the Cypripedium. It is a plant which I have never seen & therefore have been glad to examine it.2

The contrivance by which insects, after they have entered the labellum by the mouth, are forced to crawl out by one of the small lateral passages & thus get smeared with the viscid pollen, is very curious; it is exactly the same principle on which traps are made to catch insects in kitchen, namely the edge of the mouth, or large opening into the labellum being bent inwards so that the insect instead of getting out falls back.3

With my best thanks, believe me dear Sir yours faithfully | Charles Darwin


The year is established by the relationship between this letter and the letters from Arthur Rawson, 1 April [1863] and [6 April 1863] (Correspondence vol. 11).
Rawson had loaned CD a specimen of the orchid Cypripedium pubescens (greater yellow lady’s slipper; see Correspondence vol. 11, letter from Arthur Rawson, [6 April 1863] and n. 2).
In Orchids 2d ed., p. 230, CD added a description of his experiment with Cypripedium pubescens and compared the working of the labellum to insect traps.


CD thanks the sender of a Cypripedium. He finds its pollination contrivances interesting.

Letter details

Letter no.
Charles Robert Darwin
Arthur Rawson
Sent from
Source of text
American Philosophical Society (Mss.B.D25.)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 5563,” accessed on 4 August 2021,

Also published in The Correspondence of Charles Darwin, vol. 18 (Supplement)