or some while after, and drive its
inoculating-thread in again, at precisely the same place, as though
nothing had happened. Was it the same individual repeating her operation
in a cell which she had visited before but forgotten, or different
individuals coming one after the other to lay an egg in a compartment
thought to be unoccupied? I cannot say, having neglected to mark the
operators, for fear of disturbing them.

As there is nothing, except the mark of my pencil, a mark devoid of
meaning to the insect, to indicate that the auger has already been at
work there, it may easily happen that the same operator, finding under
her feet a spot already exploited by herself but effaced from her
memory, repeats the thrust of her tool in a compartment which she
believes herself to be discovering for the first time. However retentive
its memory for places may be, we cannot admit that the insect remembers
for weeks on end, as well as point by point, the topography of a nest
covering a surface of some square yards. Its recollections, if it have
any, serve it badly; the outward appearance gives it no information; and
its drill enters wherever it may happen to discover a cell, at points
that have already perhaps been pierced several times over.

It may also happen--and this appears to me the most frequent case--that
one exploiter of a cell is succeeded by a second, a third, a fourth
and others still, all fired with the newcomer's zeal because their
predecessors have left no trace of their passage. In one way or another,
the same cell is exposed to manifold layings, though its contents, the
Chalicodoma-grub, be only the bare ration of a single Leucopsis-grub.

These reiterated borings are not at all rare: I noted a score of them
on my tiles; and, in the case of some cells, the operation was repeated
before my eyes as often as four times. Nothing tells us that this number
was not exceeded in my absence. The little that I observed prevents me
from fixing any limit. And now a momentous question arises: is the egg
really laid each time that the probe enters a cell? I can see not the
slightest excuse for supposing the contrary. The ovipositor, because of
its horny nature, can have but a very dull sense of touch. The insect
is apprised of the contents of the cell only by the end of that long
horse-hair, a not very trustworthy witness, I should imagine. The
absence of resistance tells it that it has reached an empty space; and
this is pr