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Darwin Correspondence Project

From Roland Trimen   27 March 1868

71, Guildford Street.

27th. March, 1868.

My dear Mr. Darwin,

What you have sketched above seems to me to be quite in accordance with the few facts on the subject which we possess.1 I am struck with the idea of two apparently adverse tendencies at work among Moths, one tending to intensify any splendour of colour in view of sexual selection, and the other to conceal it from attracting the notice of enemies. The double end seems to be attained in those numerous species whose brightly-coloured hindwings are covered by the dull forewings when the creature is dormant or at rest, but can readily be displayed on occasion. The dull underside of many Butterflies in conjunction with a brilliant upperside seems to afford similar evidence.

Always faithfully yours, | Roland Trimen


Trimen’s letter was written on the last page of CD’s letter to him of 27 March [1868], as CD had requested.


Approves CD’s revision on coloration of moths.

Impressed with apparent adverse tendencies: one toward sexual selection, the other toward protection.

Letter details

Letter no.
Roland Trimen
Charles Robert Darwin
Sent from
London, Guildford St, 71
Source of text
DAR 82: A120v
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 6061,” accessed on 20 September 2019,

Also published in The Correspondence of Charles Darwin, vol. 16