72 
NATURAL SELECTION 
in 
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 equaiis, 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, Homa- 
locranium semi-cinctum (Colubridse), 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 (Scytalidse), 
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 eury- 
zonus and Oxyrhopus petolarius, which exactly copy its 
pattern. In Brazil Elaps lemniscatus is copied by Oxyrhopus 
trigeminus, both having black rings disposed in threes. In 
Elaps hemiprichii the ground colour appears to be black, with 
alternations of two narrow yellow bands and a broader red 
one ; and of this pattern again we have an exact double in 
