1877.] The Colors of Animals and Plants. 651 
The second class — the warning colors — are exceedingly in- 
teresting, because the object and effect of these is, not to conceal 
the object, but to make it conspicuous. To these creatures it is 
useful to be seen and recognized, the reason being that they have 
a means of defense which, if known, will prevent their enemies 
from attacking them, though it is generally not sufficient to save 
their lives if they are actually attacked. The best examples of 
these specially protected creatures consist of two extensive fami- 
lies of butterflies, the Danaidz and Acreidx, comprising many 
hundreds of species inhabiting the tropics of all parts of the 
world. ‘These insects are generally large, are all conspicuously 
and often most gorgeously colored, presenting. almost every con- 
ceivable tint and pattern; they all fly slowly, and they never at- 
tempt to conceal themselves; yet no bird, spider, lizard, or mon- 
key (all of which eat other butterflies) ever touches them. The 
reason simply is that they are not fit to eat, their juices having a 
powerful odor and taste that is absolutely disgusting to all these 
animals. Now, we see the reason of their showy colors and slow 
flight. It is good for them to be seen and recognized, for then 
they are never molested; but if they did not differ in form and 
coloring from other butterflies, or if they flew so quickly that 
their peculiarities could not be easily noticed, they would be cap- 
tured, and though not eaten would be maimed or killed. As soon 
as the cause of the peculiarities of these butterflies was recog- 
nized, it was seen that the same explanation applied to many 
other groups of animals. Thus bees and wasps and other sting- 
ing insects are showily and distinctively colored ; many soft and 
apparently defenseless beetles, and many gay-colored moths, were 
found to be as nauseous as the above-named butterflies ; other 
beetles, whose hard and glossy coats of mail render them unpala- 
table to insect-eating birds, are also sometimes showily colored ; 
and the same rule was found to apply to caterpillars, all the 
brown and green (or protectively colored species) being greedily 
eaten by birds, while showy kinds, which never hide themselves, 
— like those of the magpie, mullein, and burnet moths, — were 
Utterly refused by insectivorous birds, lizards, frogs, and spiders. 
Some few analogous examples are found among vertebrate animals. — 
Twill only mention here a very interesting case not given in my © 
former work. In his delightful book entitled The Naturalist in 
F Nicaragua, Mr. Belt tells us that there is in that country a frog 
Which is very abundant, which hops about in the day-time, which 
1 Contributions to Theory of Natural Selection, page 117, 
