ntraction and dilation, without being able to advance, without even
being able to maintain its normal position, because of the weakness of
its legs. It usually remains motionless, lying on its side, or else
displays its drowsy activity merely by feeble, wormlike movements.

By dint of these alternate contractions and dilations, indolent though
they be, the larva nevertheless contrives to turn right round in the
sort of shell with which the pseudochrysalidal integuments provide it,
when by accident it finds itself placed head downwards; and this
operation is all the more difficult inasmuch as the larva almost
exactly fills the cavity of the shell. The creature contracts, bends
its head under its belly and slides its front half over its hinder
half by wormlike movements so slow that the lens can hardly detect
them. In less than a quarter of an hour the larva, at first turned
upside down, finds itself again head uppermost. I admire this
gymnastic feat, but have some difficulty in understanding it, so small
is the space which the larva, when at rest in its cell, leaves
unoccupied, compared with that which we should be justified in
expecting from the possibility of such a reversal. The larva does not
long enjoy the privilege which enables it to resume inside its cell,
when this is moved from its original position, the attitude which it
prefers, that is to say, with its head up.

Two days, at most, after its first appearance it relapses into an
inertia as complete as that of the pseudochrysalis. On removing it
from its amber shell, we see that its faculty of contracting or
dilating at will is so completely paralysed that the stimulus of a
needle is unable to provoke it, though the integuments have retained
all their flexibility and though no perceptible change has occurred in
the organization. The irritability, therefore, which in the
pseudochrysalis is suspended for a whole year, reawakens for a moment,
to relapse instantly into the deepest torpor. This torpor will be
partly dispelled only at the moment of the passing into the nymphal
stage, to return immediately afterwards and last until the insect
attains the perfect state.

Further, on holding larvae of the third form, or nymphs enclosed in
their cells, in an inverted position, in glass tubes, we never see
them regain an erect position, however long we continue the
experiment. The perfect insect itself, during the time that it is
enclosed in the shell, cannot regain it