1877.] The Colors of Animals and Plants. 719 
so save the vital parts of the insect, while the bright patch 
on the orange-tip butterflies, which Mr. Darwin denies are pro- 
tective, may serve the same purpose. It is, in fact, somewhat 
remarkable how very generally the black spots, ocelli, or bright 
patches of color, are on the tips, margins, or disks of the wings; 
and, as the insects are necessarily visible while flying, and this is 
the time when they are most subject to attacks by insectivorous 
birds, the position of the more conspicuous parts at some distance 
from the body may be a real protection to them. Again, Mr. 
Darwin admits that the white color of the male ghost-moth may 
render it more easily seen by the female while flying about in 
the dusk, and if to this we add that it will be also more readily 
distinguished from allied species, we have a reason for diverse 
ornamentation in these insects quite sufficient to account for 
most of the facts, without believing in the selection of brilliant 
males by the females, for which there is not a particle of evi- 
dence. The facts given to show that butterflies and other insects 
can distinguish colors, and are attracted by colors similar to their 
own, are quite consistent with the view that color, which con- 
tinually tends to appear, is utilized for purposes of identification 
and distinction, when not required to be modified or suppressed 
for purposes of protection. The cases of the females of some 
species of Thecla, Callidryas, Colias, and Hipparchia, which 
have more conspicuous markings than the male, may be due to 
several causes: to obtain greater | distinction from other species, 
for protection from birds} as in the case of the yellow-under-wing 
moths, while sometimes—as in Hipparchia—the lower intensity 
of coloring in the female may lead to more contrasted markings. 
Mr. Darwin thinks that here the males have selected the more 
beautiful females, although one chief fact in support of his theory ` 
of voluntary sexual selection is, that throughout the whole animal 
kingdom the males are usually so ardent that they will accept 
any female, while the females are coy, and choose the handsom- 
est males, whence it is believed the general brilliancy of males as 
compared with females has arisen. 
Perhaps the most curious cases of sexual difference of color are 
those in which the female is very much more gayly colored than 
the male. This occurs most strikingly in some species of Pieris 
in South America, and of Diadema in the Malay islands, and 
in both cases the females resemble the uneatable Danaidæ and 
Heliconidæ, and thus gain a protection. In the case of Pieris 
a Pyrrha, P. malenka, and P. lorena, the males are plain white 
