ee has laid her egg, she leaves it for a time to go
in search of the cement needed for closing the cell; or, if she already
holds a pellet in her mandibles, this is not enough to seal it properly,
as the orifice is larger. More pellets are needed to wall up the
entrance entirely. The Dioxys would have time to strike her blow during
the mother's absences; but everything seems to suggest that she behaves
on the pebbles as she does on the tiles. She steals a march by hiding
the egg in the mass of pollen and honey.

What becomes of the Mason's egg confined in the same cell with the egg
of the Dioxys? In vain have I opened nests at every season; I have never
found a vestige of the egg nor of the grub of either Chalicodoma. The
Dioxys, whether as a larva on the honey, or enclosed in its cocoon,
or as the perfect insect, was always alone. The rival had disappeared
without a trace. A suspicion thereupon suggests itself; and the facts
are so compelling that the suspicion is almost equal to a certainty. The
parasitic grub, which hatches earlier than the other, emerges from its
hiding-place, from the midst of the honey, comes to the surface and,
with its first bite, destroys the egg of the Mason-bee, as the Sapyga
does the egg of the Osmia. It is an odious, but a supremely efficacious
method. Nor must we cry out too loudly against such foul play on the
part of a new born infant: we shall meet with even more heinous tactics
later. The criminal records of life are full of these horrors which we
dare not search too deeply. An infinitesimal creature, a barely-visible
grub, with the swaddling-clothes of its egg still clinging to it, is led
by instinct, at its first inspiration, to exterminate whatever is in its
way.

So the Mason's egg is exterminated. Was it really necessary in the
Dioxys' interest? Not in the least. The hoard of provisions is too large
for its requirements in a cell of the Chalicodoma of the Sheds; how
much more so in a cell of the Chalicodoma of the Pebbles! She eats not
a half, hardly a third of it. The rest remains as it was, untouched. We
see here, in the destruction of the Mason's egg, a flagrant waste which
aggravates the crime. Hunger excuses many things; for lack of food, the
survivors on the raft of the Medusa indulged in a little cannibalism;
but here there is enough food and to spare. When there is more than she
needs, what earthly motive impels the Dioxys to destroy a rival in
the germ stage? Why cannot