s also the pebbles of the mountain-streams
at her disposal. Near Orange, for instance, her favourite spots are the
alluvia of the Aygues, with their carpets of smooth pebbles no longer
visited by the waters. Lastly, if a cobble be wanting, the Mason-bee
will establish her nest on any sort of stone, on a mile-stone or a
boundary-wall.

The Sicilian Chalicodoma has an even greater variety of choice. Her most
cherished site is the lower surface of the projecting tiles of a roof.
There is not a cottage in the fields, however small, but shelters
her nests under the eaves. Here, each spring, she settles in populous
colonies, whose masonry, handed down from one generation to the next and
enlarged year by year, ends by covering considerable surfaces. I have
seen some of these nests, under the tiles of a shed, spreading over an
area of five or six square yards. When the colony was hard at work, the
busy, buzzing crowd was enough to make one giddy. The under side of a
balcony also pleases the Mason-bee, as does the embrasure of a disused
window, especially if it is closed by a blind whose slats allow her
a free passage. But these are popular resorts, where hundreds and
thousands of workers labour, each for herself. If she be alone, which
happens pretty often, the Sicilian Mason-bee instals herself in the
first little nook handy, provided that it supplies a solid foundation
and warmth. As for the nature of this foundation, she does not seem to
mind. I have seen her build on the bare stone, on bricks, on the wood
of a shutter and even on the window-panes of a shed. One thing only
does not suit her: the plaster of our houses. She is as prudent as her
kinswoman and would fear the ruin of her cells, if she entrusted them to
a support which might possibly fall.

Lastly, for reasons which I am still unable to explain to my own
satisfaction, the Sicilian Mason-bee often changes the position of her
building entirely, turning her heavy house of clay, which would seem
to require the solid support of a rock, into an aerial dwelling. A
hedge-shrub of any kind whatever--hawthorn, pomegranate, Christ's
thorn--provides her with a foundation, usually as high as a man's head.
The holm-oak and the elm give her a greater altitude. She chooses in the
bushy clump a twig no thicker than a straw; and on this narrow base she
constructs her edifice with the same mortar that she would employ under
a balcony or the ledge of a roof. When finished, the nest