rtition
is built to separate this cell from the next, for each larva must
have its special chamber, about a centimetre and a half (.58
inch.--Translator's Note.) long, having no communication with the
chambers adjoining. The materials employed for this partition are
bramble-sawdust, glued into a paste with the insects' saliva. Whence are
these materials obtained? Does the Osmia go outside, to gather on the
ground the rubbish which she flung out when boring the cylinder? On the
contrary, she is frugal of her time and has better things to do than to
pick up the scattered particles from the soil. The channel, as I said,
is at first uniform in size, almost cylindrical; its sides still retain
a thin coating of pith, forming the reserves which the Osmia, as a
provident builder, has economized wherewith to construct the partitions.
So she scrapes away with her mandibles, keeping within a certain radius,
a radius that corresponds with the dimensions of the cell which she is
going to build next; moreover, she conducts her work in such a way as to
hollow out more in the middle and leave the two ends contracted. In this
manner, the cylindrical channel of the start is succeeded, in the worked
portion, by an ovoid cavity flattened at both ends, a space resembling a
little barrel. This space will form the second cell.

As for the rubbish, it is utilized on the spot for the lid or cover
that serves as a ceiling for one cell and a floor for the next. Our own
master-builders could not contrive more successfully to make the best
use of their labourers' time. On the floor thus obtained, a second
ration of honey is placed; and an egg is laid on the surface of the
paste. Lastly, at the upper end of the little barrel, a partition is
built with the scrapings obtained in the course of the final work on the
third cell, which itself is shaped like a flattened ovoid. And so the
work goes on, cell upon cell, each supplying the materials for the
partition separating it from the one below. On reaching the end of the
cylinder, the Osmia closes up the case with a thick layer of the same
mortar. Then that bramble-stump is done with; the Bee will not return
to it. If her ovaries are not yet exhausted, other dry stems will be
exploited in the same fashion.

The number of cells varies greatly, according to the qualities of the
stalk. If the bramble-stump be long, regular and smooth, we may count
as many as fifteen: that, at least, is the highest figure w