oser. It would be easy for him to pull one
of them towards him with his paw, which would make the passage wider;
but this would be a movement backward, contrary to his natural impulse;
and so he does not think of it. Yet another creature that does not
reason.

The Tachytes, who stubbornly persists in tugging at her limed Mantis
and refuses to acknowledge any other method of wresting her from the
Silene's snare, shows us the Wasp in an unflattering light. What a very
poor intellect! The insect becomes only the more wonderful, therefore,
when we consider its supreme talent as an anatomist. Many a time I have
insisted upon the incomprehensible wisdom of instinct; I do so again at
the risk of repeating myself. An idea is like a nail: it is not to be
driven in save by repeated blows. By hitting it again and again, I hope
to make it enter the most rebellious brains. This time I shall attack
the problem from the other end, that is, I shall first allow human
knowledge to have its say and shall then interrogate the insect's
knowledge.

The outward structure of the Praying Mantis would of itself be enough to
teach us the arrangement of the nerve-centres which the Tachytes has to
injure in order to paralyse its victim, which is destined to be devoured
alive but harmless. A narrow and very long prothorax divides the front
pair of legs from the two hinder pairs. There must therefore be an
isolated ganglion in front and two ganglia, close to each other,
about two-fifths of an inch back. Dissection confirms this forecast
completely. It shows us three fairly bulky thoracic ganglia, arranged in
the same manner as the legs. The first which actuates the fore-legs, is
placed opposite their roots. It is the largest of the three. It is also
the most important, for it presides over the insect's weapons, over the
two powerful arms, toothed like saws and ending in harpoons. The other
two, divided from the first by the whole length of the prothorax, each
face the origin of the corresponding legs; consequently they are very
near each other. Beyond them are the abdominal ganglia, which I pass
over in silence, as the operating insect does not have to trouble about
them. The movements of the belly are mere pulsations and are in no way
dangerous.

Now let us do a little reasoning on behalf of our non-reasoning insect.
The sacrificer is weak; the victim is comparatively powerful. Three
strokes of the lancet must abolish all offensive movement. Wher