652 The Colors of Animals and Plants. [ November, 
~ never hides himself, and which is gorgeously colored with red and 
same reason wasps are imitated by moths, and ants by 
blue. Now, frogs are usually green, brown, or earth-colored, 
feed mostly at night, and are all eaten by snakes and birds. 
Having full faith in the theory of protective and warning colors, 
to which he had himself contributed some valuable facts and ob- 
servations, Mr. Belt felt convinced that this frog must be uneat- 
able. He therefore took one home, and threw it to his dtcks 
and fowls; but all refused to touch it except one young duck, 
which took the frog in its mouth, but dropped it directly, and 
went about jerking its head as if trying to get rid of something 
nasty. Here the uneatableness of the frog was predicted from 
its colors and habits, and we can have no more convincing proof 
of the truth of the theory than such previsions. 
The universal avoidance by carnivorous animals of all these 
specially protected groups, which are thus entirely free from the 
constant persecution suffered by other creatures not so protected, 
would evidently render it advantageous for any of these latter 
which were subjected to extreme persecution to be mistaken for 
the former, and for this purpose it would be necessary that they 
should have the same colors, form, and habits. Strange to say, 
wherever there is an extensive group of directly protected forms 
(division a of animals with warning colors) there are sure to be 
found a few otherwise defenseless creatures which resemble them 
externally so as to be mistaken for them, and which thus gain pe 
tection as it were on false pretenses (division b of animals with 
warning colors). This is what is called “ mimicry,” and it has 
already been very fully treated of by Mr. Bates (its discoverer), 
by myself, by Mr. Trimen, and others. Here it is only neces- 
sary to state that the uneatable Danaidæ and Acræidæ are ac 
companied by a few species of other groups of butterflies (Lepta- 
lidæ, Papilios, Diademas, and Moths) which are all really eata- 
ble, but which escape attack by their close resemblance to sone 
species of the uneatable groups found in tlie same locality. 
like manner there are a few eatable beetles which exactly resem- 
ble species of uneatable groups; and others, which are soft, a 
tate those which are uneatable through their hardness. For the 
and even poisonous snakes are mimicked by harmless snakes, 
dangerous hawks by defenseless cuckoos. How these curious a 
itations have been brought about, and the laws which pe 7 
them, have been discussed in the work already referred to | 
The third class — sexual colors — comprise all cases in 
+ 
which — 
beetles; 
