When it moves, either to flee from the upper layers of the soil, which in winter become too cold, or to install itself upon a more juicy root, it makes a road by rejecting behind it the material broken up by the teeth of its picks.

That this is its method is incontestable.
As with the larvae of Capricornis and Buprestes, it is enough for the traveller to have around it the small amount of free space necessitated by its movements.

Moist, soft, and easily compressible soil is to the larva of the Cigale what digested wood-pulp is to the others.

It is compressed without difficulty, and so leaves a vacant space.
The difficulty is that sometimes the burrow of exit from the waiting-place is driven through a very arid soil, which is extremely refractory to compression so long as it retains its aridity.

That the larva, when commencing the excavation of its burrow, has already thrust part of the detached material into a previously made gallery, now filled up and disappeared, is probable enough, although nothing in the actual condition of things goes to support the theory; but if we consider the capacity of the shaft and the extreme difficulty of making room for such a volume of debris, we feel dubious once more; for to hide such a quantity of earth a considerable empty space would be necessary, which could only be obtained by the disposal of more debris.