i866— 1872] SEXUAL SELECTION 6l 



It is curious how we hit on the same ideas. I I 

 endeavoured to show in my MS. discussion that nearly the 

 same principles account for young birds not being gaily 

 coloured in many cases, but this is too complex a point 

 for a note. 



On reading over your letter again, and on further 

 reflection, I do not think (as far as I remember my words) 

 that I expressed myself nearly strongly enough on the 

 value and beauty of your generalisation, 1 viz., that all birds 

 in which the female is conspicuously or brightly coloured 

 build in holes or under domes. I thought that this was 

 the explanation in many, perhaps most cases, but do 

 not think I should ever have extended my view to your 

 generalisation. Forgive me troubling you with this P.S. 



To A. K Wallace. Letter 430 



Down, May 5th [1867]. 



The offer of your valuable notes is most generous, but it 

 would vex me to take so much from you, as it is certain that 

 you could work up the subject very much better than I could. 

 Therefore 1 earnestly, and without any reservation, hope that 

 you will proceed with your paper, so that I return your notes. 

 You seem already to have well investigated the subject. I 

 confess on receiving your note that I felt rather flat at my 

 recent work being almost thrown away, but I did not intend 

 to show this feeling. As a proof how little advance I had 

 made on the subject, I may mention that though I had been 

 collecting facts on the colouring, and other sexual differences 

 in mammals, your explanation with respect to the females 

 had not occurred to me. I am surprised at my own stupidity, 

 but I have long recognised how much clearer and deeper 

 your insight into matters is than mine. I do ne>t know ho\ 

 far you have attended to the laws of inheritance, so wk 

 follows may be obvious to you. I have begun my discussion 

 on sexual selection by showing that new characters often 

 appear in one sex and are transmitted to that sex , and 



that from some unknown cause such characters apparently 

 appear oftener in the male than in the female. Secondly, 

 characters may be developed and be confined to the male, 



1 See Letter 203, Vol. I., p. 2S3. 



