corridors, which save labour, are in great demand; but there are not
many vacant, as the more precocious Osmiae have already taken
possession of most of them; and therefore the building of new cells
soon begins. These cells are cemented to the surface of the nest,
which thus increases in thickness every year. The edifice of cells is
not built all at once: mortar and honey alternate repeatedly. The
masonry starts with a sort of little swallow's nest, a half-cup or
thimble, whose circumference is completed by the wall against which it
rests. Picture the cup of an acorn cut in two and stuck to the surface
of the nest: there you have the receptacle in a stage sufficiently
advanced to take a first instalment of honey.

The Bee thereupon leaves the mortar and busies herself with
harvesting. After a few foraging-trips, the work of building is
resumed; and some new rows of bricks raise the edge of the basin,
which becomes capable of receiving a larger stock of provisions. Then
comes another change of business: the mason once more becomes a
harvester. A little later, the harvester is again a mason; and these
alternations continue until the cell is of the regulation height and
holds the amount of honey required for the larva's food. Thus come,
turn and turn about, more or less numerous according to the occupation
in hand, journeys to the dry and barren path, where the cement is
gathered and mixed, and journeys to the flowers, where the Bee's crop
is crammed with honey and her belly powdered with pollen.

At last comes the time for laying. We see the Bee arrive with a pellet
of mortar. She gives a glance at the cell to enquire if everything is
in order; she inserts her abdomen; and the egg is laid. Then and there
the mother seals up the home: with her pellet of cement she closes the
orifice and manages so well with the material that the lid receives