We can hardly see the possibility of a mimicry
by which the elk could escape from the wolf, or the buffalo from the
tiger. There is, however, in one group of Vertebrata such a general
similarity of form, that a very slight modification, if accompanied by
identity of colour, would produce the necessary amount of resemblance;
and at the same time there exist a number of species which it would be
advantageous for others to resemble, since they are armed with the most
fatal weapons of offence. We accordingly find that reptiles furnish us
with a very remarkable and instructive case of true mimicry.

_Mimicry among Snakes._

There are in tropical America a number of venomous snakes of the genus
Elaps, which are ornamented with brilliant colours disposed in a
peculiar manner. The ground colour is generally bright red, on which are
black bands of various widths and sometimes divided into two or three by
yellow rings. Now, in the same country are found several genera of
harmless snakes, having no affinity whatever with the above, but
coloured exactly the same. For example, the poisonous Elaps fulvius
often occurs in Guatemala with simple black bands on a coral-red ground;
and in the same country is found the harmless snake Pliocerus equalis,
coloured and banded in identically the same manner. A variety of Elaps
corallinus has the black bands narrowly bordered with yellow on the same
red ground colour, and a harmless snake, Homalocranium semicinctum, has
exactly the same markings, and both are found in Mexico. The deadly
Elaps lemniscatus has the black bands very broad, and each of them
divided into three by narrow yellow rings; and this again is exactly
copied by a harmless snake, Pliocerus elapoides, which is found along
with its model in Mexico.

But, more remarkable still, there is in South America a third group of
snakes, the genus Oxyrhopus, doubtfully venomous, and having no
immediate affinity with either of the preceding, which has also the same
curious distribution of colours, namely, variously disposed rings of
red, yellow, and black; and there are some cases in which species of all
three of these groups similarly marked inhabit the same district. For
example, Elaps mipartitus has single black rings very close together. It
inhabits the west side of the Andes, and in the same districts occur
Pliocerus euryzonus and Oxyrhopus petolarius, which exactly copy its
pattern. In Brazil Elaps lemniscatus is copied by Oxyrhopu