de, they ought,
in all logic, to serve as the basis of the law. Here, one fact says yes;
there, a thousand facts say no. To which evidence shall we lend an ear?
If we only wish to bolster up a theory, it would be prudent to listen
to neither. The how and why escapes us; what we dignify with the
pretentious title of a law is but a way of looking at things with our
mind, a very squint-eyed way, which we adopt for the requirements of our
case. Our would-be laws contain but an infinitesimal shade of reality;
often indeed they are but puffed out with vain imaginings. Such is the
law of mimesis, which explains the Green Grasshopper by the green leaves
in which this Locust settles and is silent as to the Crioceris, that
coral-red Beetle who lives on the no less green leaves of the lily.

And it is not only a mistaken interpretation: it is a clumsy pitfall
in which novices allow themselves to be caught. Novices, did I say? The
greatest experts themselves fall into the trap. One of our masters of
entomology did me the honour to visit my laboratory. I was showing
my collection of parasites. One of them, clad in black and yellow,
attracted his attention.

'This,' said he, 'is obviously a parasite of the Wasps.'

Surprised at the statement, I interposed:

'By what signs do you know her?'

'Why look: it's the exact colouring of the Wasp, a mixture of black and
yellow. It is a most striking case of mimesis.'

'Just so; nevertheless, our black-and-yellow friend is a parasite of the
Chalicodoma of the Walls, who has nothing in common, either in shape or
colour, with the Wasp. This is a Leucopsis, not one of whom enters the
Wasps' nest.'

'Then mimesis...?'

'Mimesis is an illusion which we should do well to relegate to
oblivion.'

And, with the evidence, a whole series of conclusive examples, in front
of him, my learned visitor admitted with a good grace that his first
convictions were based on a most ludicrous foundation.

A piece of advice to beginners: you will go wrong a thousand times for
once that you are right if, when anxious to obtain a premature sight of
the probable habits of an insect, you take mimesis as your guide. With
mimesis above all, it is wise, when the law says that a thing is black,
first to enquire whether it does not happen to be white.

Let us go on to more serious subjects and enquire into parasitism
itself, without troubling any longer about the costume of the parasite.
According to etymology, a