are in one packet; they number
about three hundred.

When the beak and eyes are rendered inaccessible, when the body,
moreover, has no wounds, the laying still takes place, but, this time,
in a hesitating and niggardly fashion. I pluck the bird completely, the
better to watch what happens; also, I cover the head with a paper hood
to close the usual means of access. For a long time, with jerky steps,
the mother explores the body in every direction; she takes her stand by
preference on the head, which she sounds by tapping on it with her front
tarsi. She knows that the openings which she needs are there, under
the paper; but she also knows how frail are her grubs, how powerless to
pierce their way through the strange obstacle which stops her as well
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 favor 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 armpit,
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 favorite ones.

It follows from all this that, to lay the 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. We shall see the reasons for her preference later on.

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 almos