SEXUAL SELECTION 423 



gree from their original condition; and they would thua 

 ultimately assume an appearance or coloring wholly unlike 

 that of the other members of the group to which they be- 

 longed. It should also be remembered that many species of 

 Lepidoptera are liable to considerable and abrupt variations 

 in color. A few instances have been given in this chapter; 

 and many more may be found in the papers of Mr. Bates 

 and Mr. Wallace. 



With several species the sexes are alike, and imitate the 

 two sexes of another species. But Mr. Trimen gives, in 

 the paper already referred to, three cases in which the sexes 

 of the imitated form differ from each other in color, and the 

 sexes of the imitating form differ in a like manner. Several 

 cases have also been recorded where the females alone imi- 

 tate brilliantly colored and protected species, the males re- 

 taining "the normal aspect of their immediate congeners." 

 It is here obvious that the successive variations by which 

 the female has been modified have been transmitted to her 

 alone. It is, however, probable that some of the many 

 successive variations would have been transmitted to, 

 and developed in, the males, had not such males been 

 eliminated by being thus rendered less attractive to the 

 females ; so that only those variations were preserved which 

 were from the first strictly limited in their transmission to 

 the female sex. We have a partial illustration of these re- 

 marks in a statement by Mr. Belt," that the males of some 

 of the Leptalides, which imitate protected species, still re- 

 tain in a concealed manner some of their original charac- 

 ters. Thus in the males "the upper half of the lower wing 

 is of a pure white, while all the rest of the wings is barred 

 and spotted with black, red, and yellow, like the species 

 they mimic. The females have not this white patch, and 

 the males usually conceal it by covering it with the upper 

 wing, so that I cannot imagine its being of any other use to 

 them than as an attraction in courtship, when they exhibit it 



K" "The Naturalist In Nicaragua, " 1874, p. 386. ^ 



