its permanent form at this first sitting; it has only to be thickened
and strengthened with fresh layers, a work which is less urgent and
will be done by and by. What does appear to be an urgent necessity is
the closing of the cell immediately after the egg has been religiously
deposited therein, so that there may be no danger from evilly-disposed
visitors during the mother's absence. The Bee must have serious
reasons for thus hurrying on the closing of the cell. What would
happen if, after laying her egg, she left the house open and went to
the cement-pit to fetch the wherewithal to block the door? Some thief
might drop in and substitute her own egg for the Mason-bee's. We shall
see that our suspicions are not uncalled-for. One thing is certain,
that the Mason never lays without having in her mandibles the pellet
of mortar required for the immediate construction of the lid of the
nest. The precious egg must not for a single instant remain exposed to
the cupidity of marauders.

To these particulars I will add a few general observations which will
make what follows easier to understand. So long as its circumstances
are normal, the insect's actions are calculated most rationally in
view of the object to be attained. What could be more logical, for
instance, than the devices employed by the Hunting Wasp when
paralysing her prey (Cf. "Insect Life": chapters 3 to 12 and 15 to
17.--Translator's Note.) so that it may keep fresh for her larva,
while in no wise imperilling that larva's safety? It is preeminently
rational; we ourselves could think of nothing better; and yet the
Wasp's action is not prompted by reason. If she thought out her
surgery, she would be our superior. It will never occur to anybody
that the creature is able, in the smallest degree, to account for its
skilful vivisections. Therefore, so long as it does not depart from
the path mapped out for it, the insect can perform the most sagacious