SEXUAL SELECTION 409 



wMcli compels us to believe that tlie lower surfaces have 

 here been colored for the sake of protection, leads us to 

 deny that the wings have been tipped with bright orange 

 for the same purpose, especially when this character is con- 

 fined to the males. 



Most Moths rest motionless during the whole or greater 

 part of the day with their wings depressed, and the whole 

 upper surface is often shaded and colored in an admirable 

 manner, as Mr. Wallace has remarked, for escaping detec- 

 tion. The front wings of the Bombycidse and Noctuidse, " 

 when at rest, generally overlap and conceal the hind-wings, 

 so that the latter might be brightly colored without much 

 risk; and they are in fact often thus colored. During 

 flight, moths would often be able to escape from their 

 enemies; nevertheless, as the hind-wings are then fully 

 exposed to view, their bright colors must generally have 

 been acquired at some little risk. But the following fact 

 shows how cautious we ought to be in drawing conclusions 

 on this head. The common Yellow Under-wings (Triphsena) 

 often fly about during the day or early evening, and are 

 then conspicuous from the color of their hind-wings. It 

 would naturally be thought that this would be a source 

 of danger; but Mr. J. Jenner Weir believes that it actually 

 serves them as a means of escape, for birds strike at these 

 brightly colored and fragile surfaces, instead of at the body. 

 For instance, Mr. Weir turned into his aviary a vigorous 

 specimen of Triphcena pronuba, which was instantly pursued 

 by a robin; but the bird's attention being caught by the 

 colored wings, the moth was not captured until after about 

 fifty attempts, and small portions of the wings were repeat- 

 edly broken off. He tried the same experiment in the open 

 air, with a swallow and T. fimbria; but the large size of this 

 moth probably interfered with its capture. " We are thus 

 reminded of a statement made by Mr. Wallace," namely, 



1' Mr. Wallace in "Hardwicke's Science Gossip," Sept. 1867, p. 193. 

 i« See also, on this subject, Mr. Weir's paper in "Transact. Ent. Society," 

 1869, p. 23. 



18 ''Westminster Rev.," July, 1867, p. 16. 



pescent — ^Vol. I. — 18 



