ont legs resting on the rim, inserts its abdomen in the cell; it has
the mortar ready in its mouth. Having laid the egg, it comes out and
turns round to block the door. I wave it away for a second, at the
same time planting my straw as before, a straw sticking out nearly a
centimetre. (.39 inch.--Translator's Note.) What will the Bee do? Will
she, who is scrupulous in ridding the home of the least mote of dust,
extract this beam, which would certainly prove the larva's undoing by
interfering with its growth? She could, for just now we saw her drag out
and throw away, at a distance, a similar beam.

She could and she doesn't. She closes the cell, cements the lid, seals
up the straw in the thickness of the mortar. More journeys are taken,
not a few, in search of the cement required to strengthen the cover.
Each time, the mason applies the material with the most minute care,
while giving the straw not a thought. In this way, I obtain, one after
the other, eight closed cells whose lids are surmounted by my mast, a
bit of protruding straw. What evidence of obtuse intelligence!

This result is deserving of attentive consideration. At the moment when
I am inserting my beam, the insect has its mandibles engaged: they are
holding the pellet of mortar intended for the blocking-operation. As
the extracting-tool is not free, the extraction does not take place. I
expected to see the Bee relinquish her mortar and then proceed to remove
the encumbrance. A dab of mortar more or less is not a serious business.
I had already noticed that it takes my Mason-bees a journey of three
or four minutes to collect one. The pollen-expeditions last longer, a
matter of ten or fifteen minutes. To drop her pellet, grab the straw
with her mandibles, now disengaged, remove it and gather a fresh supply
of cement would entail a loss of five minutes at most. The Bee decides
differently. She will not, she cannot relinquish her pellet; and
she uses it. No matter that the larva will perish by this untimely
trowelling: the moment has come to wall up the door; the door is walled
up. Once the mandibles are free, the extraction could be attempted, at
the risk of wrecking the lid. But the Bee does nothing of the sort: she
keeps on fetching mortar; and the lid is religiously finished.

We might go on to say that, if the Bee were obliged to depart in quest
of fresh mortar after dropping the first to withdraw the straw, she
would leave the egg unguarded and that thi