sting: the under part of the head, or rather of the first segments, which
are placed outside the coil, so that the grub's hard cranium makes a
rampart for the hinder extremity, which is less well defended. Here the
Wasp's sting enters and here only can it enter, within a narrowly
circumscribed area. One stab only of the lancet is given at this point, one
only because there is no room for more; and this is enough: the larva is
absolutely paralysed.

The nervous functions are abolished instantly; the muscular contractions
cease; and the animal uncoils like a broken spring. Henceforth motionless,
it lies on its back, its ventral surface fully exposed from end to end. On
the median line of this surface, towards the rear, near the brown patch due
to the alimentary broth contained in the intestine, the Scolia lays her egg
and without more ado, leaves everything lying on the actual spot where the
murder was committed, in order to go in search of another victim.

This is how the deed must be done: the results prove it emphatically. But
then the Cetonia-grub must possess a very exceptional structure in its
nervous organization. The larva's violent contraction leaves but a single
point of attack open to the sting, the under part of the neck, which is
doubtless uncovered when the victim tries to defend itself with its
mandibles; and yet a stab in this one point produces the most thorough
paralysis that I have ever seen. It is the general rule that larvae possess
a centre of innervation for each segment. This is so in particular with the
Grey Worm, the sacrificial victim of the Hairy Ammophila. The Wasp is
acquainted with this anatomical secret: she stabs the caterpillar again and
again, from end to end, segment by segment, ganglion by ganglion. With such
an organization the Cetonia-grub, unconquerably coiled upon itself would
defy the paralyser's surgical skill.