The young Sitares, which are also very minute, directly they issue from the egg at the entrance of the tubes of the Anthrophorus, remain motionless, assembled in a heap, and pass the whole of the winter in a state of complete abstinence. The young Cigales apparently behave in a very similar fashion. Once they have burrowed to such depths as will safeguard them from the frosts they sleep in solitude in their winter quarters, and await the return of spring before piercing some neighbouring root and taking their first repast.
I have tried unsuccessfully to confirm these deductions by observation. In April I unpotted my plant of thyme for the third time. I broke up the mould and spread it under the magnifying-glass. It was like looking for needles in a haystack; but at last I recovered my little Cigales. They were dead, perhaps of cold, in spite of the bell-glass with which I had covered the pot, or perhaps of starvation, if the thyme was not a suitable food-plant. I give up the problem as too difficult of solution.
To rear such larvæ successfully one would require a deep, extensive bed of earth which would shelter them from the winter cold; and, as I do not know what roots they prefer, a varied vegetation, so that the little creatures could choose according to their taste. These conditions are by no means impracticable, but how, in the large earthy mass, containing at least a cubic yard of soil, should we recover the atoms I had so much trouble to find in a handful of black soil from the heath? Moreover, such a laborious search would certainly detach the larva from its root.
The early subterranean life of the Cigale escapes us. That of the maturer larva is no better known. Nothing is more common, while digging in the fields to any depth, to find these impetuous excavators under the spade; but to surprise them fixed upon the roots which incontestably nourish them is quite another matter. The disturbance of the soil warns the larva of danger. It withdraws its proboscis in order to retreat along its galleries, and when the spade uncovers it has ceased to feed.
If the hazards of field-work, with its inevitable disturbance of the larvæ, cannot teach us anything of their subterranean habits, we can at least learn something of the duration of the larval stage. Some obliging farmers, who were making some deep excavations in March, were good enough to collect for me all the larvæ, large and small, unearthed in the course of their labour. The total collection amounted to several hundreds. They were divided, by very clearly marked differences of size, into three categories: the large larvæ, with rudiments of wings, such as those larvæ caught upon leaving the earth possess; the medium-sized, and the small. Each of these stages must correspond to a different age. To these we may add the larvæ produced by the last hatching of eggs, creatures too minute to be noticed by my rustic helpers, and we obtain four years as the probable term of the larvæ underground.
The length of their aerial existence is more easily computed. I hear the first Cigales about the summer solstice. A month later the orchestra has attained its full power. A very few late singers execute their feeble solos until the middle of September. This is the end of the concert. As all the larvæ do not issue from the ground at the same time, it is evident that the singers of September are not contemporary with those that began to sing at the solstice. Taking the average between these two dates, we get five weeks as the probable duration of the Cigales' life on earth.
Four years of hard labour underground, and a month of feasting in the sun; such is the life of the Cigale. Do not let us again reproach the adult insect with his triumphant delirium. For four years, in the darkness he has worn a dirty parchment overall; for four years he has mined the soil with his talons, and now the mud-stained sapper is suddenly clad in the finest raiment, and provided with wings that rival the bird's; moreover, he is drunken with heat and flooded with light, the supreme terrestrial joy. His cymbals will never suffice to celebrate such felicity, so well earned although so ephemeral.