It may be in the corner of a room, or in a hole in a wall,
or in the hollow of a bamboo; but wherever it is, the principle
is the same, although the shape of the nest may vary. Everything
is to be hermetically sealed.
The mason-fly commences by flattening the first pill of clay upon
the intended site (say the corner of a room); she then spreads it
in a thin layer over a surface of about two inches, and retires
for another ball of clay. This she dabs upon the plastic
foundation, and continues the apparently rude operation until
some twenty or thirty pills of clay are adhering at equal
distances. She then forms these into a number of neat
oval-shaped cells, about the size of a wren's egg, and in each
cell she deposits one egg. She then flies off in search of
spiders, which are to be laid tip in stores within the cells as
food for the young larvae, when hatched.
Now the transition from the larva to the fly takes place in the
cell, and occupies about six weeks from the time the egg is first
laid; thus, as the egg itself is not vivified for some weeks
after it is deposited, the spiders have to be preserved in a
sound and fresh state during that interval until the larva is in
such an advanced stage as to require food.
