the work proceeded. And the worker--in what condition is it? Let us see.

The larva is much paler in colour than those which I have caught as they
emerged. The large eyes in particular are whitish, cloudy, blurred, and
apparently blind. What would be the use of sight underground? The eyes
of the larvæ leaving their burrows are black and shining, and evidently
capable of sight. When it issues into the sunlight the future Cigale
must find, often at some distance from its burrow, a suitable twig from
which to hang during its metamorphosis, so that sight is obviously of
the greatest utility. The maturity of the eyes, attained during the time
of preparation before deliverance, proves that the larva, far from
boring its tunnel in haste, has spent a long time labouring at it.

What else do we notice? The blind, pale larva is far more voluminous
than in the mature state; it is swollen with liquid as though it had
dropsy. Taken in the fingers, a limpid serum oozes from the hinder part
of the body, which moistens the whole surface. Is this fluid, evacuated
by the intestine, a product of urinary secretion--simply the contents of
a stomach nourished entirely upon sap? I will not attempt to decide, but
for convenience will content myself with calling it urine.

Well, this fountain of urine is the key to the enigma. As it digs and
advances the larva waters the powdery debris and converts it into a
paste, which is immediately applied to the walls by the pressure of the
abdomen. Aridity is followed by plasticity. The mud thus obtained
penetrates the interstices of the rough soil; the more liquid portion
enters the substance of the soil by infiltration; the remainder becomes
tightly packed and fills up the inequalities of the walls. Thus the
insect obtains an empty tunnel, with no loose waste, as all the loosened
soil is utilised on the spot, converted into a mortar which is more