because these are too far from the places where she builds. So
long as she can find dry earth, rich in small gravel, near the pebble
chosen as the site of her nest, that is all she asks.

The Bee may either build an entirely new nest on a site as yet
unoccupied, or she may use the cells of an old nest, after repairing
them. Let us consider the former case first. After selecting her pebble,
the Mason-bee of the Walls arrives with a little ball of mortar in her
mandibles and lays it in a circular pad on the surface of the stone.
The fore-legs and above all the mandibles, which are the mason's chief
tools, work the material, which is kept plastic by the salivary fluid as
this is gradually disgorged. In order to consolidate the clay, angular
bits of gravel, the size of a lentil, are inserted separately, but only
on the outside, in the as yet soft mass. This is the foundation of the
structure. Fresh layers follow, until the cell has attained the desired
height of two or three centimetres. (Three-quarters of an inch to one
inch.--Translator's Note.)

Man's masonry is formed of stones laid one above the other and cemented
together with lime. The Chalicodoma's work can bear comparison with
ours. To economise labour and mortar, the Bee employs coarse materials,
big pieces of gravel, which to her represent hewn stones. She chooses
them carefully one by one, picks out the hardest bits, generally with
corners which, fitting one into the other, give mutual support and
contribute to the solidity of the whole. Layers of mortar, sparingly
applied, hold them together. The outside of the cell thus assumes
the appearance of a piece of rustic architecture, in which the stones
project with their natural irregularities; but the inside, which
requires a more even surface in order not to hurt the larva's tender
skin, is covered with a coat of pure mortar. This inner whitewash,
however, is put on without any attempt at art, indeed one might say
that it is ladled on in great splashes; and the grub takes care, after
finishing its mess of honey, to make itself a cocoon and hang the rude
walls of its abode with silk. On the other hand, the Anthophorae and
the Halicti, two species of Wild Bees whose grubs weave no cocoon,
delicately glaze the inside of their earthen cells and give them the
gloss of polished ivory.

The structure, whose axis is nearly always vertical and whose orifice
faces upwards so as not to let the honey escape, varies a little