54 THE COLOUES OF ANIMALS 



is exactly that of a hole, for the two membranes are 

 BO transparent that they are completely invisible. The 

 size of the apparent hole varies very greatly in the 

 numerous specimens of Kallima inacliis.^ in the Hope 

 Collection at Oxford. 



The upper sides of the wings, concealed during 

 rest, are dark, with a deep orange bar across the 

 fore-wings. I have heard a naturalist, who is ac- 

 quainted with the Indian species {Kallima inachis) in 

 its natural surroundings, object to the interpretation 

 afforded by Mr. Wallace, on the ground that he has 

 often seen the butterfly displaying the conspicuous 

 upper sides of its wings when settled, and has seen it 

 resting on inappropriate surfaces. I do not think 

 that this objection is fatal ; for butterflies only dis- 

 play their brilliant tints during the short pauses 

 between the successive flights, when they are on the 

 alert and can evade their enemies by wariness and by 

 the swiftness of their flight. Our own beautiful Eed 

 Admiral {Vanessa atalanta)^ Peacock (F. lo)^ and Small 

 Tortoiseshell (F. urticce) similarly display their bril- 

 liant colours when pausing on a flower or even on the 

 ground. But during prolonged rest, when the insects 

 are often semi- torpid and would be easily captured if 

 detected, the wings are invariably held so that the 

 sombre tints of the under sides are alone visible. 

 Hence the display of bright colours by the Indian 

 Kallima is no argument against the protective value 

 of the leaf-like appearance of the under sides ; for the 



