394 • SEXUAL SELECTION. Part II. 



male, and slightly different in some other respects. In 

 an allied Indian form, the Ijjhias glauci^e, the orange- 

 tips are fully developed in both sexes. In this Iphias 

 the under surface of the wings marvellously resembles, 

 as pointed out to me by Mr. A. Butler, a pale-coloured 

 leaf; and in our English orange-tip, the under surface 

 resembles the flower-head of the wild parsley, on which 

 it may be seen going to rest at night. 6 The same 

 reasoning power which compels us to believe that the 

 lower surfaces have here been coloured for the sake of 

 protection, leads us to deny that the wings have been 

 tipped, especially when this character is confined to the 

 males, with bright orange for the same purpose. 



Turning now to Moths : most of these rest motion- 

 less with their wings depressed during the whole or 

 greater part of the day ; and the upper surfaces of their 

 wings are often shaded and coloured in an admirable 

 manner, as Mr. Wallace has remarked, for escaping 

 detection. With most of the • Boinbycidse and Noc- 

 tuidse, 7 when at rest, the front-wings overlap and 

 conceal the hind-wings; so that the latter might be 

 brightly coloured without much risk ; and they 

 are thus coloured in many species of both families. 

 During the act of flight, moths w r ould often be able 

 to escape from their enemies ; nevertheless, as the 

 hind-wings are then fully exposed to view, their bright 

 colours must generally have been acquired at the 

 cost of some little risk. But the following fact shews 

 us how cautious we ought to be in drawing conclu- 

 sions on this head. The common yellow under-wings 



6 See the interesting observations by Mr. T. "W. Wood, ' The Stu- 

 dent,' Sept. 1868, p. 81. 



7 Mr. Wallace in ' Hardwicke's Science Gossip,' Sept. 1S67, p. 193. 



