as far down as the helical passage permits,
finds, immediately above the point which is too narrow to pass, the
space necessary for the cell of a female. This cell is succeeded by
others, wider still, always for females, arranged in a line in the same
way as in a straight tube. In the last whorl of the spiral, the diameter
would be too great for a single row. Then longitudinal partitions are
added to the transverse partitions, the whole resulting in cells of
unequal dimensions in which males predominate, mixed with a few females
in the lower storeys. The sequence of the sexes is therefore what it
would be in a straight tube and especially in a tube with a wide bore,
where the partitioning is complicated by subdivisions on the same level.
A single Snail-shell contains room for six or eight cells. A large,
rough earthen stopper finishes the nest at the entrance to the shell.

As a dwelling of this sort could show us nothing new, I chose for my
swarm the Garden Snail (Helix caespitum), whose shell, shaped like a
small, swollen Ammonite, widens by slow degrees, the diameter of the
usable portion, right up to the mouth, being hardly greater than that
required by a male Osmia-cocoon. Moreover, the widest part, in which
a female might find room, has to receive a thick stopping-plug, below
which there will often be a free space. Under all these conditions, the
house will hardly suit any but males arranged one after the other.

The collection of shells placed at the foot of each hive includes
specimens of different sizes. The smallest are 18 millimetres (.7
inch.--Translator's Note.) in diameter and the largest 24 millimetres
(.936 inch.--Translator's Note.) There is room for two cocoons, or three
at most, according to their dimensions.

Now these shells were used by my visitors without any hesitation,
perhaps even with more eagerness than the glass tubes, whose slippery
sides might easily be a little annoying to the Bee. Some of them were
occupied on the first few days of the laying; and the Osmia who
had started with a home of this sort would pass next to a second
Snail-shell, in the immediate neighbourhood of the first, to a third, a
fourth and others still, always close to one another, until her ovaries
were emptied. The whole family of one mother would thus be lodged in
Snail-shells which were duly marked with the date of the laying and a
description of the worker. The faithful adherents of the Snail-shell
were in the mi