The Wallace-Darwin Correspondence 



swung back to the old position, out of which I fear I shall 

 never get. 



I did most thoroughly enjoy my talk with you three 

 gentlemen, and especially with you, and to my great sur- 

 prise it has not knocked me up. Pray give my kindest 

 remembrances to Mrs. Wallace, and if my wife were at 

 home she would cordially join in this. — Yours very sin- 

 cerely, Ch. Darwin. 



I have had this morning a capital letter from Walsh of 

 Illinois; but details too long to give. 



Among Wallace's papers was found the following draft 

 of a letter of his to Darwin : 



9 St. Mark's Crescent, N,W. September 18, 1868. 



Dear Darwin, — The more I think of your views as to 

 the colours of females, the more difficulty I find in accept- 

 ing them, and as you are now working at the subject I 

 hope it will not interrupt you to hear '' counsel on the 

 other side.'' 



I have a ^' general '^ and a *^ special " argument to submit. 



1. Female birds and insects are generally exposed to 

 more danger than the male, and in the case of insects their 

 existence is necessary for a longer period. 



2. They therefore require in some way or other a special 

 balance of protection. 



3. Now, if the male and female were distinct species, 

 with different habits and organisations, you would, I 

 think, at once admit that a difference of colour serving to 

 make that one less conspicuous which evidently required 

 more protection than the other had been acquired by 

 Natural Selection. 



4. But you admit that variations appearing in one sex 

 are transmitted (often) to that sex only : there is therefore 



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