266 ANIMAL COLORATION. 



cannot be set down to isolation, and the females of the sombre 

 species have every opportunity, did they desire it, of selecting 

 the brightly coloured males and abandoning their lawful 

 spouses. 



The question, however, cannot either stand or fall upon its 

 probability or improbability. Actual observation can alone 

 settle the matter. 



Esthetic Sense of Butterflies. 



The case is clearly put by Mr. Scudder : 



"That butterflies liave some perception of colour in mass 

 is unquestionable. It has often been remarked that a white 

 butterfly alights by preference upon white flowers, yellow 

 butterflies upon yellow flowers. Direct observations have 

 shown that this vague opinion is founded clearly upon fact, and 

 several instances which show this, and at the same time show 

 the lack of power of perception of form have been published. 

 Thus, Christy observed in Manitoba one of the Swallow-tails 

 ' fluttering over the bushes, evidently in search of flowers. 

 As I watched it,' he says, ' it settled momentarily, and exactly 

 as if it had mistaken it for a yellow flower, on a twig of Betula 

 glandidosa bearing withered leaves of a light-yellow colour.' 

 Albert Miiller records seeing the blue Alexis of Europe fly 

 rapidly towards a very small bit of pale blue paper lying upon 

 the grass, and stop within an inch or two as if to settle, doubt- 

 less mistaking it for another of its own kind. Plateau has 

 observed Agloe urticce, [the small Tortoiseshell] of Europe fly 

 rapidly towards a white Calla, which could offer it no sweets. 

 And Jeuner Weir has noticed how the white butterflies settled 

 on the variegated leaves in his garden." 



These facts are a long way from proving so highly developed 

 an aesthetic sense as sexual selection renders necessary ; they 



