rolled. If it has nothing to acquire, if it knows all that it needs to
know, it flourishes and leaves descendants behind it. But then it possesses
innate instinct, the instinct which learns nothing and forgets nothing, the
instinct which is steadfast throughout time.

The building up of theories has never appealed to me: I suspect them one
and all. To argue nebulously upon dubious premises likes me no better. I
observe, I experiment and I let the facts speak for themselves. We have
just heard these facts. Let each now decide for himself whether instinct is
an innate faculty or an acquired habit.


CHAPTER 4. THE CETONIA-LARVA.

The Scolia's feeding-period lasts, on the average, for a dozen days or so.
By then the victuals are no more than a crumpled bag, a skin emptied of the
last scrap of nutriment. A little earlier, the russet-yellow tint announces
the extinction of the last spark of life in the creature that is being
devoured. The empty skin is pushed back to make space; the dining-room, a
shapeless cavity with crumbling walls, is tidied up a little; and the
Scolia-grub sets to work on its cocoon without further delay.

The first courses form a general scaffolding, which finds a support here
and there on the earthen walls, and consist of a rough, blood-red fabric.
When the larva is merely laid, as required by my investigations, in a
hollow made with the finger-tip in the bed of mould, it is not able to spin
its cocoon, for want of a ceiling to which to fasten the upper threads of
its network. To weave its cocoon, every spinning larva is compelled to
isolate itself in a hammock slung in an open-work enclosure, which enables
it to distribute its thread uniformly in all directions. If there be no