1102 THE BUTTEKKUKS OF NEW ENGLAND. 



reach to effect fertilization in the plant. The broad fact that flowers fertilized 

 by the wind are never gaily colored, while there are others habitually pro- 

 ducing two kinds of flowers, one oi)cn, colored and provided witli nectar 

 to attract insects, the other closed, uncolored, destitute of nectar and 

 never visited by insects seems to render this very clear. But we still need 

 to know how color originated in the equally or moi"e gaily colored butter- 

 flies which visit flowers, which the poets have been wont to compare to 

 flowers afloat. The prevailing opinion has been that this was due in the 

 first instance, as in tlie case of the birds, to sexual selection, that male 

 being chosen which surpassed in beauty. Tliis is the view held l)y Darwin ; 

 but recent discoveries in physiology and histology make it clear that but- 

 terflies have themselves no power of clear vision. They maj^ see masses of 

 color, but not definite pattern or form, and as, apparently, the disposition 

 far more even than the brilliancy of color goes to make up the beauty of 

 butterflies, this can in no sense be looked upon as a true cause. 



Tliat butterflies have some perception of color in mass is unquestionable. 

 It has often been remarked that white butterflies alight by preference upon 

 white flowers, yellow butterflies upon yellow flowers. Direct observations 

 have shown that this vague opinion is founded cleai'ly upon fact, and 

 several instances which show tiiis and at the same time show the lack of 

 power of perception of foi'm have been jjublished. Thus Christy ob- 

 served 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 glandulosa bearing withered leaves of a liglit 

 yellow color" (Proc. Ent. soc. Lond., 1885, 9). Albert Midler 

 records seeing the blue alexis of Europe fly toward a verj' small bit 

 of pale blue paper lying upon the grass and stop within an inch or 

 two of it as if to settle, doubtless mistaking it for another of its own kind. 

 Plateau has observed Aglais urticae of Europe fly rapidly toward a (bluster 

 of artificial flowers, and a species of Pieris toward a white calla which 

 could offer it no sweets. And Jenner Wier has noticed how the white 

 butterflies settled on the variegated leaves in his garden. 



Such examples as these seem to indicate that butterflies may perceive 

 color in mass but in no case indicate any further visual powers ; and since the 

 difference between the sexes is generally rather one of disposition of colors 

 than of variety in the colors themselves, though the latter is b)' no means 

 wanting, the theory of sexual selection proposed hy Darwin cannot be 

 rightly claimed to cover the general ground. Wallace, moreover, has 

 adduced strong reasons for doubting the value of this theory, even in those 

 animals against whose powers of sight no such stricture can be made, be- 

 lieving, as he does, that all differences between the sexes can be explained 

 from the fact of the greater vigor of the male, and the intensity of that 



