from its cerements--the prudent creature re-descends to the bottom of
its burrow for a longer wait. If, on the contrary, the state of the
atmosphere is favourable, the roof is broken through by a few strokes of
its claws, and the larva emerges from its tunnel.

Everything seems to prove that the burrow of the Cigale is a
waiting-room, a meteorological station, in which the larva makes a
prolonged stay; sometimes hoisting itself to the neighbourhood of the
surface in order to ascertain the external climate; sometimes retiring
to the depths the better to shelter itself. This explains the chamber
at the base of the shaft, and the necessity of a cement to hold the
walls together, for otherwise the creature's continual comings and
goings would result in a landslip.

A matter less easy of explanation is the complete disappearance of the
material which originally filled the excavated space. Where are the
twelve cubic inches of earth that represent the average volume of the
original contents of the shaft? There is not a trace of this material
outside, nor inside either. And how, in a soil as dry as a cinder, is
the plaster made with which the walls are covered?

Larvæ which burrow in wood, such as those of Capricornis and Buprestes,
will apparently answer our first question. They make their way through
the substance of a tree-trunk, boring their galleries by the simple
method of eating the material in front of them. Detached by their
mandibles, fragment by fragment, the material is digested. It passes
from end to end through the body of the pioneer, yields during its
passage its meagre nutritive principles, and accumulates behind it,
obstructing the passage, by which the larva will never return. The work
of extreme division, effected partly by the mandibles and partly by the