THE ANIMAL AND THE PUZZLE-BOX 



not discriminated by these birds, or do not give them 

 pleasurable or exciting sensations, then we have to 

 look for some reason for their gay plumes other than 

 the approbation of the female. Our experimental 

 psychologists have tested the powers of the painted 

 turtle to discriminate white and black. But one 

 fails to feel much interest in the result of such ex- 

 perimentations, be they what they may, because the 

 facts can have little or no relation to the creature's 

 life-problem. But the turtle's gay colors can it 

 discriminate those, and what part do they play in 

 its life-history? 



On the Darwinian hypothesis of sexual selection, 

 the gay colors of the painted turtle have a deep 

 significance, as do the brilliant colors of all other ani- 

 mals. Does the turtle or his mate discriminate these 

 colors? is he attracted by them? do they play any 

 part at all in the turtle's real life? Our common 

 box tortoise has striking and beautiful color-pat- 

 terns on its shell, often suggesting Chinese charac- 

 ters. Can the laboratory naturalist find out their 

 significance, or that of the brilliant markings of 

 many of the lizards and salamanders; do these ani- 

 mals see and know their own decorations? Or the 

 many brilliant beetles and butterflies are they 

 color-blind also? A. G. Mayer has proved conclu- 

 sively that the promethea moth has no color-sense. 

 The male of this moth has blackish wings and the 

 female reddish-brown. Mayer caused the two sexes 

 195 



