s casts
around for a favourable spot and digs her burrow. During the process of
excavation, she returns from time to time to her Spider; she nibbles at
the prize, feels, touches it here and there, as though taking stock of
its plumpness and congratulating herself on the plentiful provender;
then she returns to her burrow and goes on digging. Should anything
alarm or distress her, she does not merely inspect her Spider: she also
brings her a little closer to her work-yard, but never fails to lay her
on the top of a tuft of verdure. These are the manoeuvres of which I can
avail myself to gauge the elasticity of the Wasp's memory.

While the Pompilus is at work on the burrow, I seize the prey and place
it in an exposed spot, half a yard away from its original position.
The Pompilus soon leaves the hole to enquire after her booty and goes
straight to the spot where she left it. This sureness of direction, this
faithful memory for places can be explained by repeated previous visits.
I know nothing of what has happened beforehand. Let us take no notice
of this first expedition; the others will be more conclusive. For the
moment, the Pompilus, without the least hesitation, finds the tuft of
grass whereon her prey was lying. Then come marches and counter-marches
upon that tuft, minute explorations and frequent returns to the exact
spot where the Spider was deposited. At last, convinced that the
prize is no longer there, the Wasp makes a leisurely survey of the
neighbourhood, feeling the ground with her antennae as she goes. The
Spider is descried in the exposed spot where I had placed her. Surprise
on the part of the Pompilus, who goes forward and then suddenly steps
back with a start:

'Is it alive?' she seems to ask. 'Is it dead? Is it really my Spider?
Let us be wary!'

The hesitation does not last long: the huntress grabs her victim,
drags her backwards and places her, still high up, on a second tuft of
herbage, two or three steps away from the first. She then goes back
to the burrow and digs for a while. For the second time, I remove the
Spider and lay her at some distance, on the bare ground. This is the
moment to judge of the Wasp's memory. Two tufts of grass have served as
temporary resting-places for the game. The first, to which she returned
with such precision, the Wasp may have learnt to know by a more or less
thorough examination, by reiterated visits that escaped my eye; but the
second has certainly made but a