fly does not expose her worms to disproportionate falls. Can she know
beforehand that, when the chrysalides break, her winged family, knocking
with a sudden flight against the sides of a tall chimney, will be unable
to get out? This foresight would be in agreement with the rules which
order maternal instinct according to future needs.

But when the fall does not exceed a certain depth, the budding worms of
the flesh fly are dropped without a qualm, as all our experiments show.
This principle has a practical application which is not without its
value in matters of domestic economy. It is as well that the wonders of
entomology should sometimes give us a hint of commonplace utility.

The usual meat safe is a sort of large cage with a top and bottom
of wood and four wire gauze sides. Hooks fixed into the top are used
whereby to hang pieces which we wish to protect from the flies. Often,
so as to employ the space to the best advantage, these pieces are simply
laid on the floor on the cage. With these arrangements, are we sure of
warding off the fly and her vermin?

Not at all. We may protect ourselves against the Bluebottle, who is not
much inclined to lay her eggs at a distance from the meat; but there is
still the flesh fly, who is more venturesome and goes more briskly to
work and who will slip the grubs through a hole in the meshes and drop
them inside the safe. Agile as they are and well able to crawl, the
worms will easily reach anything on the floor; the only things secure
from their attacks will be the pieces hanging from the ceiling. It is
not in the nature of maggots to explore the heights, especially if this
implies climbing down a string in addition.

People also use wire gauze dish covers. The trellised dome protects the
contents even less than does the meat safe. The flesh fly takes no heed
of it. She can drop her worms through the meshes on the covered joint.

Then what are we to do? Nothing could be simpler. We need only wrap
the birds which we wish to preserve--thrushes, partridges, snipe and so
on--in separate paper envelopes; and the same with our beef and mutton.
This defensive armor alone, while leaving ample room for the air to
circulate, makes any invasion by the worms impossible, even without a
cover or a meat safe: not that paper possesses any special preservative
virtues, but solely because it forms an impenetrable barrier. The
Bluebottle carefully refrains from laying her eggs upon it and the f