18661872] SEXUAL SELECTION 73 



believe that I can explain (in a general way) all the phenomena of sexual Letter 440 

 ornaments and colours by laws of development aided by simple ' Natural 

 Selection." He finally rejected Mr. Darwin's theory that colours " have 

 been developed by the preference of the females, the more ornamented 

 males becoming the parents of each successive generation." Darwinism, 

 1889, p. 285. See also Letters 442, 443, 449, 450, etc. 



Down, April I5th, [1868]. 



I have been deeply interested by your admirable article on 

 birds' nests. I am delighted to see that we really differ very 

 little, not more than two men almost always will. You do 

 not lay much or any stress on new characters spontaneously 

 appearing in one sex (generally the male), and being trans- 

 mitted exclusively, or more commonly only in excess, to that 

 sex. I, on the other hand, formerly paid far too little attention 

 to protection. I had only a glimpse of the truth ; but even 

 now I do not go quite as far as you. I cannot avoid thinking 

 rather more than you do about the exceptions in nesting to 

 the rule, especially the partial exceptions, i.e., when there is 

 some little difference between the sexes in species which build 

 concealed nests. I am not quite satisfied about the incubating 

 males ; there is so little difference in conspicuousness between 

 the sexes. I wish with all my heart I could go the whole 

 length with you. You seem to think that male birds probably 

 select the most beautiful females ; I must feel some doubt on 

 this head, for I can find no evidence of it. Though I am 

 writing so carping a note, I admire the article thoroughly. 



And now I want to ask a question. When female 

 butterflies are more brilliant than their males you believe 

 that they have in most cases, or in all cases, been rendered 

 brilliant so as to mimic some other species, and thus escape 

 danger. But can you account for the males not having been 

 rendered equally brilliant and equally protected ? : Although 

 it may be most for the welfare of the species that the female 

 should be protected, yet it would be some advantage, certainly 



1 See Wallace in the Westminster Review, July, 1867, p. 37, on the 

 protection to the female insect afforded by its resemblance either to an 

 inanimate object or to another insect protected by its unpalatableness. 

 The cases are discussed in relation to the much greater importance (to 

 the species as a whole) of the preservation of the female insect with her 

 load of eggs than the male who may safely be sacrificed after pairing. 

 See Letter 189, note 3. 



