quarter or a
third of its full growth. The long neck plunged into the victim's belly
is rather difficult to extract, because of the need of molesting the
creature as little as possible. I succeed, by means of a little patience
and repeated strokes with the tip of a paint-brush. I now turn the
Cetonia-larva over, back uppermost, at the bottom of the little hollow
made by pressing my finger in the layer of mould. Lastly, I place the
Scolia on its victim's back. Here is my grub under the same conditions
as just now, with this difference, that the back and not the belly of
its victim is presented to its mandibles.

I watch it for a whole afternoon. It writhes about; it moves its little
head now in this direction, now in that, frequently laying it on the
Cetonia, but without fixing it anywhere. The day draws to a close; and
still it has accomplished nothing. There are restless movements, nothing
more. Hunger, I tell myself, will eventually induce it to bite. I am
wrong. Next morning I find it more anxious than the day before and still
groping about, without resolving to fix its mandibles anywhere. I
leave it alone for half a day longer without obtaining any result. Yet
twenty-four hours of abstinence must have awakened a good appetite,
above all in a creature which, if left undisturbed, would not have
ceased eating.

Excessive hunger cannot induce it to nibble at an unlawful spot. Is this
due to feebleness of the teeth? By no means: the Cetonia's skin is no
tougher on the back than on the belly; moreover, the grub is capable of
perforating the skin when it leaves the egg; a fortiori, it must be more
capable of doing so now that it has attained a sturdy growth. Thus we
see no lack of ability, but an obstinate refusal to nibble at a point
which ought to be respected. Who knows? On this side perhaps the grub's
dorsal vessel would be wounded, its heart, an organ indispensable to
life. The fact remains that my attempts to make the grub tackle its
victim from the back have failed. Does this mean that it entertains the
least suspicion of the danger which it might incur were it to produce
putrefaction by awkwardly carving its victuals from the back? It would
be absurd to give such an idea a moment's consideration. Its refusal is
dictated by a preordained decree which it is bound to obey.

My Scolia-grubs would die of starvation if I left them on their victim's
back. I therefore restore matters as they were, with the Cetonia-larva