grubs, sheltered by too thin a wall, have to suffer from excess of
heat in summer and of cold in winter?

Without arguing all this out, the Bee nevertheless acts wisely. When
all the cells are finished, she builds a thick cover over the group,
formed of a material, impermeable to water and a bad conductor of
heat, which acts as a protection at the same time against damp, heat
and cold. This material is the usual mortar, made of earth mixed with
saliva, but on this occasion with no small stones in it. The Bee
applies it pellet by pellet, trowelful by trowelful, to the depth of a
centimetre (.39 inch--Translator's Note.) over the cluster of cells,
which disappear entirely under the clay covering. When this is done,
the nest has the shape of a rough dome, equal in size to half an
orange. One would take it for a round lump of mud which had been
thrown and half crushed against a stone and had then dried where it
was. Nothing outside betrays the contents, no semblance of cells, no
semblance of work. To the inexperienced eye, it is a chance splash of
mud and nothing more.

This outer covering dries as quickly as do our hydraulic cements; and
the nest is now almost as hard as a stone. It takes a knife with a
strong blade to break open the edifice. And I would add, in
conclusion, that, under its final form, the nest in no way recalls the
original work, so much so that one would imagine the cells of the
start, those elegant turrets covered with stucco-work, and the dome of
the finish, looking like a mere lump of mud, to be the product of two
different species. But scrape away the crust of cement and we shall
easily recognize the cells below and their layers of tiny pebbles.

Instead of building a brand-new nest, on a hitherto unoccupied