The Wallace-Darwin Correspondence 



just read a paper at the Geological Society. It seems to 

 me supported by quite as much evidence as Kamsay's 

 *' Lakes '- ; but Ramsay, I understand, will have none of it 

 — as yet. — Believe me yours very faithfully, 



Alfred R. Wallace. 



Downy Beckenham, Kent, August 31, 1877. 



My dear Wallace, — I am very much obliged to you for 

 sending your article, which is very interesting and appears 

 to me as clearly written as it can be. You will not be sur- 

 prised that I differ altogether from you about sexual colours. 

 That the tail of the peacock and his elaborate display of it 

 should be due merely to the vigour, activity, and vitality 

 of the male is to me as utterly incredible as my views are 

 to you. Mantegazza published a few years ago in Italy a 

 somewhat similar view. I cannot help doubting about re- 

 cognition through colour : our horses, dogs, fowls, and 

 pigeons seem to know their own species, however differ- 

 ently the individuals may be coloured. I wonder whether 

 you attribute the odoriferous and sound-producing organs, 

 when confined to the males, to their greater \dgour, etc. ? I 

 could say a good deal in opposition to you, but my argu- 

 ments would have no weight in your eyes, and I do not 

 intend to write for the public anything on this or any other 

 difficult subject. By the way, I doubt whether the term 

 voluntary in relation to sexual selection ought to be em- 

 ployed : w^hen a man is fascinated by a pretty girl it can 

 hardly be called voluntary, and I suppose that female 

 animals are charmed or excited in nearly the same man- 

 ner by the gaudy males. 



Three essays have been published lately in Germany 

 which would interest you : one by Weismann, who shows 

 that the coloured stripes on the caterpillars of Sphinx 

 are beautifully protective : and birds were frightened away 



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