Bramble-Bees and Others | Page 5

a cubit. This sheath is next divided, by partitions,
into more or less numerous storeys, each of which forms the cell of a
larva. Others, less well-endowed with strength and implements, avail
themselves of the old galleries of other insects, galleries that have been
abandoned after serving as a home for their builder's family. Their only
work is to make some slight repairs in the ruined tenement, to clear the
channel of its lumber, such as the remains of cocoons and the litter of
shattered ceilings, and lastly to build new partitions, either with a
plaster made of clay or with a concrete formed of pith-scrapings
cemented with a drop of saliva.
You can tell these borrowed dwellings by the unequal size of the
storeys. When the worker has herself bored the channel, she
economizes her space: she knows how costly it is. The cells, in that

case, are all alike, the proper size for the tenant, neither too large nor
too small. In this box, which has cost weeks of labour, the insect has to
house the largest possible number of larvae, while allotting the
necessary amount of room to each. Method in the superposition of the
floors and economy of space are here the absolute rule.
But there is evidence of waste when the insect makes use of a bramble
hollowed by another. This is the case with Tripoxylon figulus. To
obtain the store-rooms wherein to deposit her scanty stock of Spiders,
she divides her borrowed cylinder into very unequal cells, by means of
slender clay partitions. Some are a centimetre (.39 inch.--Translator's
Note.) deep, the proper size for the insect; others are as much as two
inches. These spacious rooms, out of all proportion to the occupier,
reveal the reckless extravagance of a casual proprietress whose
title-deeds have cost her nothing.
But, whether they be the original builders or labourers touching up the
work of others, they all alike have their parasites, who constitute the
third class of bramble-dwellers. These have neither galleries to
excavate nor victuals to provide; they lay their egg in a strange cell; and
their grub feeds either on the provisions of the lawful owner's larva or
on that larva itself.
At the head of this population, as regards both the finish and the
magnitude of the structure, stands the Three-pronged Osmia (Osmia
tridentata, DUF. and PER.), to whom this chapter shall be specially
devoted. Her gallery, which has the diameter of a lead pencil,
sometimes descends to a depth of twenty inches. It is at first almost
exactly cylindrical; but, in the course of the victualling, changes occur
which modify it slightly at geometrically determined distances. The
work of boring possesses no great interest. In the month of July, we see
the insect, perched on a bramble-stump, attack the pith and dig itself a
well. When this is deep enough, the Osmia goes down, tears off a few
particles of pith and comes up again to fling her load outside. This
monotonous labour continues until the Bee deems the gallery long
enough, or until, as often happens, she finds herself stopped by an
impassable knot.
Next comes the ration of honey, the laying of the egg and the
partitioning, the last a delicate operation to which the insect proceeds
by degrees from the base to the top. At the bottom of the gallery, a pile

of honey is placed and an egg laid upon the pile; then a partition 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