; the narrowest
measure six or seven. (About a quarter of an inch.--Translator's Note.)
In the latter, if the bottom suit her, the Osmia sets to work bringing
pollen and honey. If the bottom do not suit her, if the sorghum-pith
plug with which I have closed the rear-end of the tube be too irregular
and badly-joined, the Bee coats it with a little mortar. When this
small repair is made, the harvesting begins.

In the wider tubes, the work proceeds quite differently. At the moment
when the Osmia disgorges her honey and especially at the moment when,
with her hind-tarsi, she rubs the pollen-dust from her ventral brush,
she needs a narrow aperture, just big enough to allow of her passage. I
imagine that in a straitened gallery the rubbing of her whole body
against the sides gives the harvester a support for her brushing-work.
In a spacious cylinder this support fails her; and the Osmia starts
with creating one for herself, which she does by narrowing the channel.
Whether it be to facilitate the storing of the victuals or for any
other reason, the fact remains that the Osmia housed in a wide tube
begins with the partitioning.

Her division is made by a dab of clay placed at right angles to the
axis of the cylinder, at a distance from the bottom determined by the
ordinary length of a cell. The wad is not a complete round; it is more
crescent-shaped, leaving a circular space between it and one side of
the tube. Fresh layers are swiftly added to the dab of clay; and soon
the tube is divided by a partition which has a circular opening at the
side of it, a sort of dog-hole through which the Osmia will proceed to
knead the Bee-bread. When the victualling is finished and the egg laid
upon the heap, the whole is closed and the filled-up partition becomes
the bottom of the next cell. Then the same method is repeated, that is
to say, in front of the just completed ceiling a second partition is
built, again with a side-passage, which is stouter, owing to its
distance from the centre, and better able to withstand the numerous
comings and goings of the housewife than a central orifice, deprived of
the direct support of the wall, could hope to be. When this partition
is ready, the provisioning of the second cell is effected; and so on
until the wide cylinder is completely stocked.

The building of this preliminary party-wall, with a narrow, round
dog-hole, for a chamber to which the victuals will not be brought until
later is not restr