The Wallace-Darwin Correspondence 



doubt be found someone to battle with me over your facts, 

 on this hard problem. 



With best wishes and kind regards to Mrs. Darwin and 

 all your family, believe me, dear Darwin, yours very faith- 

 fully? Alfred E. Wallace. 



Down, Bromley, Kent, S.E. October 6, 1868. 



My dear Wallace, — Your letter is very valuable to me, 

 and in every way very kind. I will not inflict a long 

 answer, but only answer your queries. There are breeds 

 (viz. Hamburgh) in which both sexes differ much from 

 each other and from both sexes of G, lanJciva; and both 

 sexes are kept constant by selection. 



The comb of Spanish c? has been ordered to be upright 

 and that of Spanish ? to lop over, and this has been 

 effected. There are sub -breeds of game fowl, with $s 

 very distinct and cjs almost identical; but this appar- 

 ently is the result of spontaneous variation without special 

 selection. 



I am very glad to hear of the case of $ birds of paradise. 



I have never in the least doubted the possibility of modi- 

 fying female birds alone for protection; and I have long 

 believed it for butterflies : I have wanted only evidence for 

 the females alone of birds having had their colours modi- 

 fied for protection. But then I believe that the variations 

 by which a female bird or butterfly could get or has got 

 protective colouring have probably from the first been 

 variations limited in their transmission to the female sex; 

 and so with the variations of the male, where the male is 

 more beautiful than the female, I believe the variations 

 were sexually limited in their transmission to the males. 

 I am delighted to hear that you have been hard at work 

 on your MS. — Yours most sincerely, qjj^ Darwin. 



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