of the paralysis, therefore, demands that the motor ganglia, at least the
three thoracic ganglia, shall be packed in close contact opposite this
point. This determines the selection of Weevils and Buprestes, both of
which are so strongly armoured.

But where the prey has only a soft skin, incapable of stopping the sting,
the concentrated nervous system is no longer necessary, for the operator,
versed in the anatomical secrets of her victim, knows to perfection where
the centres of innervation lie; and she wounds them one after another, if
need be from the first to the last. Thus do the Ammophilae go to work when
dealing with their caterpillars and the Sphex-wasps when dealing with their
Locusts, Ephippigers and Crickets.

With the Scoliae we come once again to a soft prey, with a skin penetrable
by the sting no matter where it be attacked. Will the tactics of the
caterpillar-hunters, who stab and stab again, be repeated here? No, for the
difficulty of movement under ground prohibits so complicated an operation.
Only the tactics of the paralysers of armour-clad insects are practicable
now, for, since there is but one thrust of the dagger, the feat of surgery
is reduced to its simplest terms, a necessary consequence of the
difficulties of an underground operation. The Scoliae, then, whose destiny
it is to hunt and paralyse under the soil the victuals for their family,
require a prey made highly vulnerable by the close assemblage of the nerve-
centres, as are the Weevils and Buprestes of the Cerceres; and this is why
it has fallen to their lot to share among them the larvae of the
Scarabaeidae.

Before they obtained their allotted portion, so closely restricted and so
judiciously selected; before they discovered the precise and almost
mathematical point at which the sting must enter to produce a sudden and a