and interferes with the work of her ovipositor. The cowl
inspires her with profound distrust. Despite the tempting bait of the
veiled head, not an egg is laid on the wrapper, slight though it may
be.

Weary of vain attempts to compass this obstacle, the Fly at last
decides in favour of other points, but not on the breast, belly, or
back, where the hide would seem too tough and the light too intrusive.
She needs dark hiding-places, corners where the skin is very delicate.
The spots chosen are the cavity of the axilla, corresponding with our
arm-pit, and the crease where the thigh joins the belly. Eggs are laid
in both places, but not many, showing that the groin and the axilla are
adopted only reluctantly and for lack of a better spot.

With an unplucked bird, also hooded, the same experiment failed: the
feathers prevent the Fly from slipping into those deep places. Let us
add, in conclusion, that, on a skinned bird, or simply on a piece of
butcher's meat, the laying is effected on any part whatever, provided
that it be dark. The gloomiest corners are the favourite ones.

It follows from all this that, to lay her eggs, the Bluebottle picks
out either naked wounds or else the mucous membranes of the mouth or
eyes, which are not protected by a skin of any thickness. She also
needs darkness.

The perfect efficiency of the paper bag, which prevents the inroads of
the worms through the eye-sockets or the beak, suggests a similar
experiment with the whole bird. It is a matter of wrapping the body in
a sort of artificial skin which will be as discouraging to the Fly as
the natural skin. Linnets, some with deep wounds, others almost intact,
are placed one by one in paper envelopes similar to those in which the
nursery-gardener keeps his seeds, envelopes just folded, without being
stuck. The paper is quite ordinary and of middling thickness. Torn
pieces of newspaper serve the purpose.

These sheaths with the corpses inside them are freely exposed to the
air, on the table in my study, where they are visited, according to the
time of day, in dense shade and in bright sunlight. Attracted by the
effluvia from the dead meat, the Bluebottles haunt my laboratory, the
windows of which are always open. I see them daily alighting on the
envelopes and very busily exploring them, apprised of the contents by
the gamy smell. Their incessant coming and going is a sign of intense
cupidity; and yet none of them decides to lay on the bags. Th