truncated and open.

There are other quarters that suit the Three-horned Osmia, who is not
particular, it seems to me, and will make shift with any hiding-place,
so long as it has the requisite conditions of diameter, solidity,
sanitation and kindly darkness. The most original dwellings that I know
her to occupy are disused Snail-shells, especially the house of the
Common Snail (Helix aspersa). Let us go to the slope of the hills thick
with olive-trees and inspect the little supporting-walls which are
built of dry stones and face the south. In the crevices of this insecure
masonry, we shall reap a harvest of old Snail-shells, plugged with earth
right up to the orifice. The family of the Three-horned Osmia is settled
in the spiral of those shells, which is subdivided into chambers by mud
partitions.

Let us inspect the stone-heaps, especially those which come from the
quarry-works. Here we often find the Field-mouse sitting on a grass
mattress, nibbling acorns, almonds, olive-stones and apricot-stones. The
Rodent varies his diet: to oily and farinaceous foods he adds the Snail.
When he is gone, he has left behind him, under the overhanging stones,
mixed up with the remains of other victuals, an assortment of empty
shells, sometimes plentiful enough to remind me of the heap of Snails
which, cooked with spinach and eaten country-fashion on Christmas Eve,
are flung away next day by the housewife. This gives the Three-horned
Osmia a handsome collection of tenements; and she does not fail to
profit by them. Then again, even if the Field-mouse's conchological
museum be lacking, the same broken stones serve as a refuge for
Garden-snails who come to live there and end by dying there. When we see
Three-horned Osmiae enter the crevices of old walls and of stone-heaps,
there is no doubt about their occupation: they are getting free lodgings
out of the old Snail-shells of those labyrinths.

The Horned Osmia, who is less common, might easily also be less
ingenious, that is to say, less rich in varieties of houses. She seems
to scorn empty shells. The only homes that I know her to inhabit are the
reeds of the hurdles and the deserted cells of the Masked Anthophora.

All the other Osmiae whose method of nest-building I know work with
green putty, a paste made of some crushed leaf or other; and none of
them, except Latreille's Osmia, is provided with the horned or tubercled
armour of the mud-kneaders. I should like to know what plant