e is exactly that which they would have assumed under the
influence of a shock or any other cause of alarm. The Buprestis has
his legs symmetrically folded against his chest and belly; the
Geotrupes has his outspread, stretched in disorder, rigid and as
though attacked by catalepsy. You could not tell if they were dead or
alive.

They are not dead. In a minute or two, the Geotrupes' tarsi twitch,
the palpi quiver, the antennae wave gently to and fro. Then the
fore-legs move; and a quarter of an hour has not elapsed before the
other legs are struggling. The activity of the insect made motionless
by the concussion of a shock would reawaken in precisely the same
fashion.

As for the Buprestis, he is in a state of inertia so profound that at
first I really believe him to be dead. He recovers during the night;
and next day I find him in possession of his usual activity. The ether
experiment, which I took care to stop at the moment when it produced
the desired effect, has not been fatal to him; but it has had much
more serious consequences for him than for the Geotrupes. The insect
more sensitive to the alarm due to concussion or to a fall of
temperature is also the more sensitive to the action of ether.

Thus the enormous difference which I observe in these two insects,
with regard to the inertia provoked by a shock or by handling them in
one's fingers, is explained by nice differences of impressionability.
Whereas the Buprestis remains motionless for nearly an hour, the
Geotrupes is struggling violently after a minute or two. And even then
I rarely attain this limit.

In what respect has the Geotrupes, to defend itself, less need of the
stratagem of simulated death than the Black Buprestis, well protected
by his massive build and his armour, which is so hard that it resists
the point of a pin and even of a needle? We should be perplexed by the
same question in respect of a multitude of insects, some of which
remain motionless while others do not; and we could not possibly
foresee what would happen from the genus of the subject, its form, or
its way of living.

_Buprestis tenebrionis_, for example, exhibits a persistent inertia.
Will it be the same, because of similarity of structure, with other
members of the same group? Not at all. My chance finds provide me with
the Brilliant Buprestis (_B. rutilans_, FAB.), and the Nine-spotted
Buprestis (_Ptosima novemmaculata_, FAB.). The first resists all my
attempts. The splen