slight impression on her memory. She
adopted it without any studied choice; she stopped there just long
enough to hoist her Spider to the top; she saw it for the first time and
saw it hurriedly, in passing. Is that rapid glance enough to provide an
exact recollection? Besides, there are now two localities to be modelled
in the insect's memory: the first shelf may easily be confused with the
second. To which will the Pompilus go?

We shall soon find out: here she comes, leaving the burrow to pay a
fresh visit to the Spider. She runs straight to the second tuft, where
she hunts about for a long time for her absent prey. She knows that it
was there, when last seen, and not elsewhere; she persists in looking
for it there and does not once think of going back to the first perch.
The first tuft of grass no longer counts; the second alone interests
her. And then the search in the neighbourhood begins again.

On finding her game on the bare spot where I myself have placed it, the
Pompilus quickly deposits the Spider on a third tuft of grass; and the
experiment is renewed. This time, the Pompilus hurries to the third
tuft when she comes to look after her Spider; she hurries to it without
hesitation, without confusing it in any way with the first two, which
she scorns to visit, so sure is her memory. I do the same thing a couple
of times more; and the insect always returns to the last perch, without
worrying about the others. I stand amazed at the memory of that pigmy.
She need but catch a single hurried glimpse of a spot that differs in
no wise from a host of others in order to remember it quite well,
notwithstanding the fact that, as a miner relentlessly pursuing her
underground labours, she has other matters to occupy her mind. Could our
own memory always vie with hers? It is very doubtful. Allow the Red Ant
the same sort of memory; and her peregrinations, her returns to the nest
by the same road are no longer difficult to explain.

Tests of this kind have furnished me with some other results worthy of
mention. When convinced, by untiring explorations, that her prey is no
longer on the tuft where she laid it, the Pompilus, as we were saying,
looks for it in the neighbourhood and finds it pretty easily, for I am
careful to put it in an exposed place. Let us increase the difficulty
to some extent. I dig the tip of my finger into the ground and lay the
Spider in the little hole thus obtained, covering her with a tiny leaf.
Now