e. The invisible attracts her quite as much as the visible.

She stays awhile on the lattice of the mouth, inspects it attentively;
but, whether because circumstances failed to serve me, or because the
wire network inspired her with distrust, I never saw her dab her eggs
upon it for certain. As her evidence was doubtful, I had recourse to
the Flesh-fly (Sarcophaga carnaria).

This Fly is less finicking in her preparations, she has more faith in
the strength of her worms, which are born ready-formed and vigorous,
and easily shows me what I wish to see. She explores the trellis-work,
chooses a mesh through which she inserts the tip of her abdomen, and,
undisturbed by my presence, emits, one after the other, a certain
number of grubs, about ten or so. True, her visits will be repeated,
increasing the family at a rate of which I am ignorant.

The new-born worms, thanks to a slight viscidity, cling for a moment to
the wire-gauze; they swarm, wriggle, release themselves and leap into
the chasm. It is a nine-inch drop at least. When this is done, the
mother makes off, knowing for a certainty that her offspring will shift
for themselves. If they fall on the meat, well and good; if they fall
elsewhere, they can reach the morsel by crawling.

This confidence in the unknown factor of the precipice, with no
indication but that of smell, deserves fuller investigation. From what
height will the Flesh-fly dare to let her children drop? I top the
test-tube with another tube, the width of the neck of a claret-bottle.
The mouth is closed either with wire-gauze or with a paper cover with a
slight cut in it. Altogether, the apparatus measures twenty-five inches
in height. No matter: the fall is not serious for the lithe backs of
the young grubs; and, in a few days, the test-tube is filled with
larvae, in which it is easy to recognize the Flesh-fly's family by the
fringed coronet that opens and shuts at the maggot's stern like the
petals of a little flower. I did not see the mother operating: I was
not there at the time; but there is no doubt possible of her coming,
nor of the great dive taken by the family: the contents of the
test-tube furnish me with a duly authenticated certificate.

I admire the leap and, to obtain one better still, I replace the tube
by another, so that the apparatus now stands forty-six inches high. The
column is erected at a spot frequented by Flies, in a dim light. Its
mouth, closed with a wire-gauze cover, rea