96 - MAN [Chap. VIII 



Letter 461 about isolation when I wrote in Chapter IV. on the circum- 

 stances favourable to Natural Selection. No doubt there 

 remains an immense deal of work to do on " Artbildung." 

 I have only opened a path for others to enter, and in the 

 course of time to make a broad and clear high-road. I am 

 especially glad that you are turning your attention to sexual 

 selection. I have in this country hardly found any naturalists 

 who agree with me on this subject, even to a moderate extent. 

 They think it absurd that a female bird should be able to 

 appreciate the splendid plumage of the male ; but it would 

 take much to persuade me that the peacock does not spread 

 his gorgeous tail in the presence of the female in order to 

 fascinate or excite her. The case, no doubt, is much more 

 difficult with insects. I fear that you will find it difficult to 

 experiment on diurnal lepidoptera in confinement, for I have 

 never heard of any of these breeding in this state. 1 I was 

 extremely pleased at hearing from Fritz Muller that he liked 

 my chapter on lepidoptera in the Descent of Alan more than 

 any other part, excepting the chapter on morals. 



Letter 462 To H. Miiller. 



Down [May, 1872]. 



I have now read with the greatest interest your essay, 2 

 which contains a vast amount of matter quite new to me. I 

 really have no criticisms or suggestions to offer. The per- 

 fection of the gradation in the character of bees, especially 

 in such important parts as the mouth-organs, was altogether 

 unknown to me. You bring out all such facts very clearly 

 by your comparison with the corresponding organs in the 

 allied hymenoptera. How very curious is the case of bees 

 and wasps having acquired, independently of inheritance from 

 a common source, the habit of building hexagonal cells and 



1 We are indebted to Mr. Bateson for the following note : " This 

 belief does not seem to be well founded, for since Darwin's time several 

 species of Rhopalocera (e.g. Pieris, Pararge, Caenonymphd) have been 

 successfully bred in confinement without any special difficulty ; and by 

 the use of large cages members even of strong-flying genera, such as 

 Vanessa, have been induced to breed." 



2 " Anwendung der Darwin'schen Lehre auf Bienen," Verhandl. 

 d. naturhist. Vereins fiir fireuss. Rheinld. u. West/., 1872. References 

 to Miiller's paper occur in the second edition of the Descent of Man. 



