ly in the
rear and bristling all over with fleshy protuberances. The creature's
papillae are set on its sides like the teeth of a comb; at the rear,
they lengthen and spread into a fan; on the back, they are shorter and
arranged in four longitudinal rows. The last section but one carries two
short, bright red breathing tubes, standing aslant and joined to each
other. The fore part, near the pointed mouth, is of a darker, brownish
color. This is the biting and motor apparatus, seen through the skin and
consisting of two fangs. Taken all round, the grub is a pretty little
thing, with its bristling whiteness, which gives it the appearance of
a tiny snowflake. But this elegance does not last long: grown big and
strong, the bumblebee fly's grub becomes soiled with sanies, turns a
russety brown and crawls about in the guise of a hulking porcupine.

What becomes of it when it leaves the egg? This my warehousing jar tells
me, partly. Unable to keep its balance on sloping surfaces, it drops
to the bottom of the receptacle, where I find it, daily, as hatched,
wandering restlessly. Things must happen likewise at the wasps'.
Incapable of standing on the slant of the paper wall, the newborn
grubs slide to the bottom of the underground cavity, which contains,
especially at the end of the summer, a heaped up provender of deceased
wasps and dead larvae removed from the cells and flung outside the
house, all nice and gamy, as proper maggot's food should be. The
Volucella's offspring, themselves maggots, notwithstanding their
snowy apparel, find in this charnel house victuals to their liking,
incessantly renewed. Their fall from the high walls might well be
not accidental, but rather a means of reaching, quickly and without
searching, the good things down at the bottom of the cavern. Perhaps,
also, some of the white grubs, thanks to the holes that make the wrapper
resemble a spongy cover, manage to slip inside the Wasps' nest. Still,
most of the Volucella's grubs, at whatever stage of their development,
are in the basement of the burrow, among the carrion remains. The
others, those settled in the wasps' home itself, are comparatively few.

These returns are enough to show us that the grubs of the bumblebee fly
do not deserve the bad reputation that has been given them. Satisfied
with the spoils of the dead, they do not touch the living; they do not
ravage the wasps' nest: they disinfect it.

Experiment confirms what we have learnt in t