lends itself excellently to the operations which I am expecting to see
them commence. Yet apparently it will not answer the purpose.

Under natural conditions a little wandering might well be indispensable.
Spots as soft as my bed of earth from the roots of the briar-heather,
purged of all hard bodies and finely sifted, are rare in nature. Coarse
soils are more usual, on which the tiny creatures could make no
impression. The larva must wander at hazard, must make a pilgrimage of
indefinite duration before finding a favourable place. Very many, no
doubt, perish, exhausted by their fruitless search. A voyage of
exploration in a country a few inches wide evidently forms part of the
curriculum of young Cigales. In my glass prison, so luxuriously
furnished, this pilgrimage is useless. Never mind: it must be
accomplished according to the consecrated rites.

At last my wanderers grow less excited. I see them attack the earth with
the curved talons of their fore-limbs, digging their claws into it and
making such an excavation as the point of a thick needle would enter.
With a magnifying-glass I watch their picks at work. I see their talons
raking atom after atom of earth to the surface. In a few minutes there
is a little gaping well. The larva climbs downwards and buries itself,
henceforth invisible.

On the morrow I turn out the contents of the vase without breaking the
mould, which is held together by the roots of the thyme and the wheat. I
find all my larvæ at the bottom, arrested by the glass. In twenty-four
hours they had sunk themselves through the entire thickness of the
earth--a matter of some four inches. But for obstacle at the bottom they
would have sunk even further.