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 the Wasp, while in quest of her lost prey, happens to walk
over this leaf, to pass it again and again without suspecting that the
Spider lies beneath, for she goes and continues her vain search
farther off. Her guide, therefore is not scent, but sight.
Nevertheless, she is constantly feeling the ground with her antennae.
What can be the function of those organs? I do not know, although I
assert that they are not olfactory organs. The Ammophila, in search of
her Grey Worm, had already led me to make the same assertion; I now