INTRODUCTION 
3 
Yet again very many insects of various orders bear such a 
striking resemblance in form, or colour, or both, to the substances, 
vegetable or mineral, upon which they habitually repose as to be 
difficult of detection when at rest. They appear moreover in 
numerous instances to seek out as resting places objects like them- 
selves with a view to concealment, and not infrequently they adopt 
an attitude which increases their resemblance to their surroundings. 
Now in the preceding paragraphs the words “ mimic,” “ model,” 
and the phrase “ seeking out . . . with a view to concealment,” are 
used in a metaphorical and not in a literal sense. 
The form of mimicry sketched out above will always be associated 
with the name of Bates, but Fritz Muller has familiarized us with 
the fact that distasteful insects in many cases appear to mimic one 
another. They are said to “ form,” or “ be drawn into associations ” 
which “ exhibit common warning colours,” thereby sharing the risks 
involved in the education of young birds, which it would appear do 
not instinctively distinguish between the palatable and unpalatable. 
Here again many of the expressions used are metaphorical. 
So far as the writer knows, there is no naturalist of repute who 
for one moment imagines that in any literal sense the fly mimics 
the wasp, or the palatable butterfly mimics the distasteful. There 
are probably very few naturalists who believe that, for example, a 
yellow butterfly hunting about for a yellow leaf on which to settle, 
does so with the conscious idea of getting thereby protection from 
its foes. 
That an insect should consciously assume a certain attitude with 
a view to concealment is of course conceivable, that it should choose 
a special background for the same purpose is also conceivable. That 
an insect by any conscious effort on its part could assume the form, 
or even the colour of another insect is utterly inconceivable. 
Of course what is really meant is, that such and such an insect 
has been successful in the struggle for existence owing to its 
resemblance in form, or colour, or habits to such and such another 
insect which started better equipped for the contest, and that the 
constant elimination of the less protected individuals has gradually 
perfected the “mimicry.” For brevity’s sake the words “mimic,” 
“model” and the like will be used throughout this work—the 
metaphor is too convenient to be laid aside. 
That the Struggle for Existence is severe and does actually result 
in the Survival of the Fittest is a belief which I share with nearly 
all field naturalists of experience. But if this be true, this process— 
conveniently if inaccurately termed Natural Selection—-must be a 
