MAYER: COLOR AND COLOR-PATTERNS. 
251 
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, Yanessa urticae, Y. 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 appears 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 brown-yellow ground color, which may be 
observed 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 
which form the whitish band in the middle of the front edge of the 
fore wing appear during the last days of development, just before 
the completion of the final color-pattern. 
Both van Bemmelen and Urech have shown that in Yanessa 
urticae the order of appearance of the various colors is the same as 
in Pyrameis cardui. The first color to appear in Yanessa 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 Yanessa 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 yellow of the mature wings. 
Almost contemporaneous with 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 
