ide, near the narrow passage. The maggots' mother has her own
logic, her prudent foresight. She knows how feeble her wee grubs will
be, how powerless to cut their way through an obstacle of any
resistance; and so, despite the temptation of the smell, she refrains
from laying, so long as she finds no entrance through which the
new-born worms can slip unaided.

I wanted to know whether the colour, the shininess, the degree of
hardness and other qualities of the obstacle would influence the
decision of a mother obliged to lay her eggs under exceptional
conditions. With this object in view, I employed small jars, each
baited with a bit of butcher's meat. The respective lids were made of
different-coloured paper, of oil-skin, or of some of that tin-foil,
with its gold or coppery sheen, which is used for sealing
liqueur-bottles. On not one of these covers did the mothers stop, with
any desire to deposit their eggs; but, from the moment that the knife
had made the narrow slit, all the lids were, sooner or later, visited
and all, sooner or later, received the white shower somewhere near the
gash. The look of the obstacle, therefore, does not count; dull or
brilliant, drab or coloured: these are details of no importance; the
thing that matters is that there should be a passage to allow the grubs
to enter.

Though hatched outside, at a distance from the coveted morsel, the
new-born worms are well able to find their refectory. As they release
themselves from the egg, without hesitation, so accurate is their
scent, they slip beneath the edge of the ill-joined lid, or through the
passage cut by the knife. Behold them entering upon their promised
land, their reeking paradise.

Eager to arrive, do they drop from the top of the wall? Not they!
Slowly creeping, they make their way down the side of the jar; they use
their fore-part, ever in quest of information, as a crutch and grapnel
in one. They reach the meat and at once instal themselves upon it.

Let us continue our investigation, varying the conditions. A large
test-tube, measuring nine inches high, is baited at the bottom with a
lump of butcher's meat. It is closed with wire-gauze, whose meshes, two
millimetres wide (.078 inch.--Translator's Note.), do not permit of the
Fly's passage. The Bluebottle comes to my apparatus, guided by scent
rather than sight. She hastens to the test-tube, whose contents are
veiled under an opaque cover, with the same alacrity as to the open
tub