The Evidence from Sexual Characters. 195 



conclusion is in accordance with the demands of our hy- 

 pothesis, although he himself has given a different ex- 

 planation, which will be discussed in the next chapter. 

 He says : 



"No language suffices to describe the splendor of the 

 males of some tropical butterflies. Even within the 

 same genus we often find species presenting an extraor- 

 dinary difference between the sexes, while others have 

 their sexes closely alike. Thus in the South American 

 genus Epicafia, Mr. Bates, to whom I am much indebted 

 for most of the following facts, and for looking over 

 this whole discussion, informs me that he knows twelve 

 species, the two sexes of which haunt the same stations, 

 and therefore cannot have been differently affected by 

 external conditions. 



"In nine of these species the males rank among the 

 most brilliant of all butterflies, and differ so greatly from 

 the comparatively plain females that they were formerly 

 placed in distinct genera. The females of these nine 

 species resemble each other in their general type of col- 

 oration, and likewise resemble both sexes in several 

 allied genera, found in various parts of the world. 

 Hence, in accordance with the descent theory, we may 

 infer that these nine species, and probably all the others 

 of the genus, are descended from an ancestral form 

 which was colored in nearly the same manner. In the 

 tenth species the female still retains the same general 

 coloring, hut the male resembles her, so that he is col- 

 ored in a much less gaudy and contrasted manner than 

 the males of the previous species. In the eleventh and 

 twelfth species, the females depart from the type of col- 

 oring which is usual with their sex in this genus, for 

 they are gayly decorated in nearly the same manner as 

 the males, but in a somewhat less degree." 



