e date beside it. This
information was to be utilized when the Leucopsis finished her labours.

When the perforators are gone, I proceed with my examination of the
nests, covered with my hieroglyphics, the pencilled notes. One result,
one which I fully expected, compensates me straightway for all my weary
waitings. Under each spot marked in black, under each spot whence I
saw the ovipositor withdrawn, I always find a cell, with not a single
exception. And yet there are intervals of solid stone between the
cells: the partition-walls alone would account for some. Moreover, the
compartments, which are very irregularly disposed by a swarm of toilers
who all work in their own sweet way, have great irregular cavities
between them, which end by being filled up with the general plastering
of the nest. The result of this arrangement is that the massive portions
cover almost the same space as the hollow portions. There is nothing
outside to show whether the underlying regions are full or empty. It is
quite impossible for me to decide if, by digging straight down, I shall
come to a hollow cell or to a solid wall.

But the insect makes no mistake: the excavations under my pencil-marks
bear witness to that; it always directs its apparatus towards the hollow
of a cell. How is it apprised whether the part below is empty or full?
Its organs of information are undoubtedly the antennae, which feel the
ground. They are two fingers of unparalleled delicacy, which pry
into the basement by tapping on the part above it. Then what do those
puzzling organs perceive? A smell? Not at all; I always had my doubts of
that and now I am certain of the contrary, after what I shall describe
in a moment. Do they perceive a sound? Are we to treat them as a
superior kind of microphone, capable of collecting the infinitesimal
echoes of what is full and the reverberations of what is empty? It is an
attractive idea, but unfortunately the antennae play their part equally
well on a host of occasions when there are no vaults to reverberate. We
know nothing and are perhaps destined never to know anything of the real
value of the antennal sense, to which we have nothing analogous; but,
though it is impossible for us to say what it does perceive, we are at
least able to recognize to some extent what it does not perceive and, in
particular, to deny it the faculty of smell.

As a matter of fact, I notice, with extreme surprise, that the great
majority of the cells