III PROTECTIVE RESEMBLANCES AMONG ANIMALS 87 
seldom reversed. Going on a little further, we find birds, 
reptiles, and insects so tinted and mottled as exactly to 
match the rock, or bark, or leaf, or flower, they are accustomed 
to rest upon,—and thereby effectually concealed. Another 
step in advance, and we have insects which are formed as 
well as coloured so as exactly to resemble particular leaves, 
or sticks, or mossy twigs, or flowers; and in these cases very 
peculiar habits and instincts come into play to aid in the 
deception and render the concealment more complete. We 
now enter upon a new phase of the phenomena, and come to 
creatures whose colours neither conceal them nor make them 
like vegetable or mineral substances; on the contrary, they 
are conspicuous enough, but they completely resemble some 
other creature of a quite different group, while they differ 
much in outward appearance from those with which all 
essential parts of their organisation show them to be really 
closely allied. They appear like actors or masqueraders 
dressed up and painted for amusement, or like swindlers 
endeavouring to pass themselves off for well-known and 
respectable members of society. What is the meaning of 
this strange travesty? Does Nature descend to imposture or 
masquerade? We answer, she does not. Her principles are 
too severe. There is a use in every detail of her handiwork. 
The resemblance of one animal to another is of exactly the 
same essential nature as the resemblance to a leaf, or to bark, 
or to desert sand, and answers exactly the same purpose. In 
the one case the enemy will not attack the leaf or the bark, 
and so the disguise is a safeguard; in the other case it is 
found that for various reasons the creature resembled is 
passed over, and not attacked by the usual enemies of its 
order, and thus the creature that resembles it has an equally 
effectual safeguard. We are plainly shown that the disguise 
is of the same nature in the two cases, by the occurrence in the 
same group of one species resembling a vegetable substance, 
while another resembles a living animal of another group ; 
and we know that the creatures resembled possess an im- 
munity from attack, by their being always very abundant, 
by their being conspicuous and not concealing themselves, 
and by their having generally no visible means of escape from 
their enemies ; while, at the same time, the particular quality 
