Color and Pattern and their Uses 



597 



completely formed and merely lack pigment. In about forty-eight hours 

 after this (see Fig. 784, a) the ground-color of the wings changes to a dirty 

 yellow. It is interesting to note that the white spots which adorn the mature 

 wings remain pure white. Fig. 784, b, illustrates the next stage, where the 

 black has begun to appear in the region beyond the cell. The nervures 



FIG. 785. Diagrammatic series showing development of color-pattern in pupal wings 

 of the promethea moth, Callosamia promethea; female wings in vertical series at left, 

 male at right. (After Mayer; one-half natural size.) 



themselves, however, remain white. Fig. 784, c, shows a still later condition, 

 where the dirty yellow ground-color has deepened into rufous, and the black 

 has deepened and increased in area and has also begun to appear along the 

 edges of the nervures. In Fig. 784. d, the black has finally suffused the 

 nervures, the base of the wing and the submedlan nervure being the only 



