questions that presented themselves to my mind when for
the first time, in 1855, I observed the facts which I have just
related. Three years of assiduous observation enabled me to add one of
its most astonishing chapters to the story of the formation of
insects.

After collecting a fairly large number of these enigmatical shells
containing adult Sitares, I had the satisfaction of observing, at
leisure, the emergence of the perfect insect from the shell, the act
of pairing and the laying of the eggs. The shell is easily broken; a
few strokes of the mandibles, distributed at random, a few kicks are
enough to deliver the perfect insect from its fragile prison.

In the glass jars in which I kept my Sitares I saw the pairing follow
very closely upon the first moments of freedom. I even witnessed a
fact which shows emphatically how imperious, in the perfect insect, is
the need to perform, without delay, the act intended to ensure the
preservation of its race. A female, with her head already cut out of
the shell, is anxiously struggling to release herself entirely; a
male, who has been free for a couple of hours, climbs on the shell
and, tugging here and there, with his mandibles, at the fragile
envelope, strives to deliver the female from her shackles. His efforts
are soon crowned with success; and, though the female is still three
parts swathed in her swaddling-bands, the coupling takes place
immediately, lasting about a minute. During the act, the male remains
motionless on the top of the shell, or on the top of the female when
the latter is entirely free. I do not know whether, in ordinary
circumstances, the male occasionally thus helps the female to gain her
liberty; to do so he would have to penetrate into a cell containing a
female, which, after all, is not beyond his powers, seeing that he has
been able to escape from his own. Still, on the actual site of the
cells, the coupling is generally performed at the entrance to the
galleries of the Anthophorae; and then neither of the sexes drags
about with it the least shred of the shell from which it has emerged.

After mating, the two Sitares proceed to clean their legs and antennae
by drawing them between their mandibles; then each goes his own way.
The male cowers in a crevice of the earthen bank, lingers for two or
three days and perishes. The female also, after getting rid of her
eggs, which she does without delay, dies at the entrance to the
corridor in which the e