400 SEXUAL SELECTION. [Part II. 



as I am informed by Mr. Wallace, some protected species 

 inhabiting the same region. The female of Diadema 

 anomala is rich purple-brown with almost the whole 

 surface glossed with satiny blue, and she closely imitates 

 the Euploea mida?nus 9 " one of the commonest butter- 

 flies of the East ; " while the male is bronzy or olive- 

 brown, with only a slight blue gloss on the outer parts 

 of the wings. 28 Both sexes of this Diadema and of D. 

 bolina follow the same habits of life, so that the differ- 

 ences in color between the sexes cannot be accounted 

 for by exposure to different conditions ; 29 even if this ex- 

 planation were admissible in other instances. 30 



The above cases, of female butterflies which are more 

 brightly-colored than the males, show us, firstly, that 

 variations have arisen in a state of nature in the female 

 sex, and have been transmitted exclusively, or almost ex- 

 clusively, to the same sex ; and, secondly, that this form 

 of inheritance has not been determined through natural 

 selection. For, if we assume that the females, before they 

 became brightly colored in imitation of some protected 

 kind, were exposed during each season for a longer period 

 to danger than the males, or if we assume that they 

 could not escape so swiftly from their enemies, we can 

 understand how they alone might originally have acquired 

 through natural selection and sexually-limited inheritance 

 their present protective colors. But, except on the prin- 

 ciple of these variations having been transmitted exclu- 

 sively to the female offspring, we cannot understand why 

 the males should have remained dull-colored; for it would 



28 Wallace, "Notes on Eastern Butterflies," 'Transact. Ent. Soc.' 

 1809, p. 287. 



29 Wallace, in 'Westminster Review,' July, 1867,- p. 37; and in 

 ' Journal of Travel and Nat. Hist.' vol. i. 1868, p. 88. 



80 See remarks by Messrs. Bates and Wallace, in ' Proc. Ent. Soc' 

 Nov. 19, 1806, p. xxxix. 



