LETTERS. 205 



experiments. If you read German, I believe I could find 

 Weismann's essays and lend them to you. In your present 

 interesting case I really do not know what to think : it 

 seems rather bold to attribute the 2 coloured forms to nat. 

 selection, before some advantage can be pointed out. May 

 not the female revert in some cases 1 I do not doubt that 

 the intermediate form could be eliminated as you suggest. 



" I wish that my opinion could have been of any 

 value. . . . 



" I remain yours very faithfully, " CH. DARWIN." 



This last letter, with others that followed it, direct- 

 ing Meldola's attention to Weismann's " Studies in 

 the Theory of Descent," resulted in the English trans- 

 lation which is so admirably rendered and edited. 

 Many of the later letters are concerned with the 

 progress of this publication. The remarks about 

 dimorphic butterflies referred to Meldola's observa- 

 tion, that in one of those years in which C olios edusa 

 was extremely abundant, a whole series of forms had 

 been taken transitional between the normal orange 

 female and the white variety helice : 



" Sept. 27 [1877]. " Down. 



" MY DEAR SIR, It is impossible for F. M. [Fritz Mtiller] 

 to object to anything which you have said in your very in- 

 teresting little essay. I just allude to Butterflies preferring 

 certain colours at p. 317 of 2nd Edit?.- of the Descent and 

 to the case of the species of Castnia p. 315 which has orna- 

 mented hinder wings and displays them, whilst 2 other 

 species have plain hind wings and do not display them. My 

 son, who has charge of my library, returns home to-night and 

 then we will search for Weismann. He gives splendid case 

 of caterpillar with coloured ocelli like true eyes, and which 

 frightened away birds. 



" Yours sincerely, " CH. DARWIN." 



