392 SEXUAL SELECTION. Part II. 



as we can judge, either for protection or as an attraction 

 between the sexes. With many species of butterflies 

 the upper surfaces of the wings are obscurely coloured, 

 and this in all probability leads to their escaping ob- 

 servation and danger. But butterflies when at rest 

 would be particularly liable to be attacked by their 

 enemies; and almost all the kinds when resting raise 

 their wings vertically over their backs, so that the lower 

 sides alone are exposed to view. Hence it is this side 

 which in many cases is obviously coloured so as to 

 imitate the surfaces on which these insects commonly 

 rest. Dr. Bossier, I believe, first noticed the similarity 

 of the closed wings of certain Yanessaa and other butter- 

 flies to the bark of trees. Many analogous and striking 

 facts could be given. The most interesting one is that 

 recorded by Mr. Wallace 5 of a common Indian and 

 Sumatran butterfly (Kallima), which disappears like 

 magic when it settles in a bush ; for it hides its head 

 and antennae between its closed wings, and these in 

 form, colour, and veining cannot be distinguished from 

 a withered leaf together with the footstalk. In some 

 other cases the lower surfaces of the wings are brilliantly 

 coloured, and yet are protective ; thus in Theda rubi 

 the wings when closed are of an emerald green and re- 

 semble the young leaves of the bramble, on which this 

 butterfly in the spring may often be seen seated. 



Although the obscure tints of the upper or under 

 surface of many butterflies no doubt serve to conceal 

 them, yet we cannot possibly extend this view to 

 the brilliant and conspicuous colours of many kinds, 

 such as our admiral and peacock Vanessae, our white 



5 See the interesting article in the * Westminster Eeview,' July, 1867, 

 p. 10. A woodcut of the Kallima is given by Mr. Wallace in ' Hard- 

 wicke's ' Science Gossip,' Sept. 1867, p. 196. 



