, so
as always to have a portion of fresh meat. With its mouth assiduously
applied to the unhappy creature's skin, the lethal grub fills itself and
waxes fat, while the fostering larva collapses and shrivels, retaining
just enough life, however, to resist decomposition. All that remains of
the decanted corpse is the skin, which, when softened in water and blown
out, swells into a balloon without the least escape of gas, thus
proving the continuity of the integument. All the same, the apparently
unpunctured bladder has lost its contents. It is a repetition of what
the Anthrax has shown us, with this difference, that the Leucopsis
seems not so well skilled in the delicate work of absorbing the victim.
Instead of the clean white granule which is the sole residue when
the Fly has finished her joint, the insect with the long probe has a
plateful of leavings, not seldom soiled with the brownish tinge of
food that has gone bad. It would seem that, towards the end, the act of
consumption becomes more savage and does not disdain dead meat. I also
notice that the Leucopsis is not able to get up from dinner or to sit
down to it again as readily as the Anthrax. I have sometimes to tease
him with the point of a hair-pencil in order to make him let go; and,
once he has left the joint, he hesitates a little before putting his
mouth to it again. His adhesion is not the mere result of a kiss like
that of a cupping-glass; it can only be explained by hooks that need
releasing.

I now see the use of the microscopic mandibles. Those two delicate
spikes are incapable of chewing anything, but they may very well serve
to pierce the epidermis with an aperture smaller than that made by the
finest needle; and it is through this puncture that the Leucopsis sucks
the juices of his prey. They are instruments made to perforate the bag
of fat which slowly, without suffering any internal injury, is emptied
through an opening repeated here and there. The Anthrax' cupping-glass
is here replaced by piercers of exceeding sharpness and so short that
they cannot hurt anything beyond the skin. Thus do we see in operation,
with a different sort of implements, that wise system which keeps the
provisions fresh for the consumer.

It is hardly necessary to say, to those who have read the story of the
Anthrax, that this kind of feeding would be impossible with a victim
whose tissues possessed their final hardness. The Mason-bee's grub is
therefore emptied by the