that she is still working at the cell which is really hers.

After leaving her for a time in possession of the strange nest, I give
her back her own. This fresh change passes unperceived by the Bee: the
work is continued in the cell restored to her at the point which it had
reached in the substituted cell. I once more replace it by the strange
nest; and again the insect persists in continuing its labour. By thus
constantly interchanging the strange nest and the proper nest, without
altering the actual site, I thoroughly convinced myself of the Bee's
inability to discriminate between what is her work and what is not.
Whether the cell belong to her or to another, she labours at it with
equal zest, so long as the basis of the edifice, the pebble, continues
to occupy its original position.

The experiment receives an added interest if we employ two neighbouring
nests the work on which is about equally advanced. I move each to where
the other stood. They are not much more than thirty inches a part. In
spite of their being so near to each other that it is quite possible for
the insects to see both homes at once and choose between them, each Bee,
on arriving, settles immediately on the substituted nest and continues
her work there. Change the two nests as often as you please and you
shall see the two Mason-bees keep to the site which they selected and
labour in turn now at their own cell and now at the other's.

One might think that the cause of this confusion lies in a close
resemblance between the two nests, for at the start, little expecting
the results which I was to obtain, I used to choose the nests which I
interchanged as much alike as possible, for fear of disheartening the
Bees. I need not have taken this precaution: I was giving the insect
credit for a perspicacity which it does not possess. Indeed, I now
take two nests which are extremely unlike each other, the only point of
resemblance being that, in each case, the toiler finds a cell in which
she can continue the work which she is actually doing. The first is an
old nest whose dome is perforated with eight holes, the apertures of the
cells of the previous generation. One of these cells has been repaired;
and the Bee is busy storing it. The second is a nest of recent
construction, which has not received its mortar dome and consists of
a single cell with its stucco covering. Here too the insect is busy
hoarding pollen-paste. No two nests could present greater dif