MAYER: COLOR AND COLOR-PATTERNS. 177 



vations at sufficiently close intervals of time, and was, therefore, 

 led into some misstatements, which have been corrected by van 

 Bemmelen ('89) and Urech ('91). 



Van Bemmelen carried out an elaborate research upon the 

 development of the various spots and colors upon the wings of 

 Pyrameis cardui, Vanessa urticae, V. io, Pieris brassicae, and a few 

 other forms. He discusses in detail the time and manner of appear- 

 ance of all of the different spots upon the wing. Into these details 

 we shall not follow him, but shall merely present his general con- 

 clusions regarding the development of the various colors. In Pieris 

 brassicae it apj^ears that during the first days of the pupal stage the 

 wings are colorless and transparent ; after a few days, however, the 

 fore wings become opaque, and white ; later the hind wing, also, 

 goes through the same changes. The wings then remain unaltered 

 until about two days before the butterfly issues. Then, very sud- 

 denly, the black spots and the yellow ground tone of the under 

 sides appear. "White is thus the primary color ; black and yellow 

 secondary. The first color to make its appearance in the case of 

 Pyrameis cardui is a bro\vn-yellow ground color, which may be 

 ol)served in pupae four days old. The hind wings are at this time 

 somewhat darker than the fore wings. The color then changes from 

 darker brown to cinnamon-brown. The black spots appear later upon 

 this delicate reddish brown ground color. The three fused spots 

 Avhich form the whitish band in the middle of the front edge of the 

 fore wing appear during the last days of develojjment, just before 

 the completion of the final color-pattern. 



Both van Bemmelen and Urech have shown that in Vanessa 

 urticae the order of ajjpearance of the various colors is the same as 

 in Pyrameis cardui. The first color to appear in Vanessa urticae is 

 a faint reddish tinge ; this deepens and forms the ground color, and 

 later the black spots appear upon it. 



Urech ('91) has made a careful study of the development of the 

 colors upon the pupal wings of Vanessa io. The wings are at first 

 wholly white. Then in a restricted area of this white is noticed the 

 appearance of a yellow, which forms the yelloA\' of the mature wings. 

 Almost contemporaneous Math the development of the yellow comes 

 the red, which appears in another part of the primitively white field, 

 and gradually deepens in color until it forms the brownish red 

 ground color of the adult wings. Still later another portion of the 

 primitive white changes into the black of the mature wing. The 



