The form of the primary larva of the Cigale is eminently adapted to its conditions and facilitates its escape.  The tunnel in which the egg is hatched is very narrow, leaving only just room for passage.  Moreover, the eggs are arranged in a row, not end to end, but partially overlapping.  The larva escaping from the hinder ranks has to squeeze past the empty shells, still in position, of the eggs which have already hatched, so that the narrowness of the passage is increased by the empty egg-shells.  Under these conditions the larva as it will be presently, when it has torn its temporary wrappings, would be unable to effect the difficult passage.  With the encumbrance of antennae, with long limbs spreading far out from the axis of the body, with curved, pointed talons which hook themselves into their medium of support, everything would militate against a prompt liberation.  The eggs in one chamber hatch almost simultaneously.  It is therefore essential that the first-born larvae should hurry out of their shelter as quickly as possible, leaving the passage free for those behind them.  Hence the boat-like shape, the smooth hairless body without projections, which easily squeezes its way past obstructions.  The primary larva, with its various appendages closely wrapped against its body by a common sheath, with its fish-like form and its single and only partially movable limb, is perfectly adapted to make the difficult passage to the outer air.

This phase is of short duration.  Here, for instance, a migrating larva shows its head, with its big black eyes, and raises the broken fibres of the entrance.  It gradually works itself forward, but so slowly that the magnifying-glass scarcely reveals its progress.  At the end of half an hour at the shortest we see the entire body of the creature; but the orifice by which it is escaping still holds it by the hinder end of the body.

Then, without further delay, the coat which it wears for this rough piece of work begins to split, and the larva skins itself, coming out of its wrappings head first.  It is then the normal larva; the only form known to Reaumur.  The rejected coat forms a suspensory thread, expanding at its free end to form a little cup.  In this cup is inserted the end of the abdomen of the larva, which, before allowing itself to fall to earth, takes a sun-bath, grows harder, stretches itself, and tries its strength, lightly swinging at the end of its life-line.

This little flea, as Reaumur calls it, first white, then amber-coloured, is precisely the larva which will delve in the earth.  The antennae, of fair length, are free and waving to and fro; the limbs are bending at their articulations; the fore-limbs, which are relatively powerful, open and shut their talons.  I can scarcely think of any more curious spectacle than that of this tiny gymnast hanging by its tail, swinging to the faintest breath, and preparing in the air for its entry into the world.  It hangs there for a variable period; some larvae let themselves fall at the end of half an hour; others spend hours in their long-stemmed cup; some even remain suspended until the following day.