These dwellings are pits about a foot deep, perpendicular at first and
then bent elbow-wise. The average diameter is an inch. On the edge of
the hole stands a kerb, formed of straw, bits and scraps of all sorts and
even small pebbles, the size of a hazel-nut. The whole is kept in place
and cemented with silk. Often, the Spider confines herself to drawing
together the dry blades of the nearest grass, which she ties down with
the straps from her spinnerets, without removing the blades from the
stems; often, also, she rejects this scaffolding in favour of a masonry
constructed of small stones. The nature of the kerb is decided by the
nature of the materials within the Lycosa's reach, in the close
neighbourhood of the building-yard. There is no selection: everything
meets with approval, provided that it be near at hand.

Economy of time, therefore, causes the defensive wall to vary greatly as
regards its constituent elements. The height varies also. One enclosure
is a turret an inch high; another amounts to a mere rim. All have their
parts bound firmly together with silk; and all have the same width as the
subterranean channel, of which they are the extension. There is here no
difference in diameter between the underground manor and its outwork, nor
do we behold, at the opening, the platform which the turret leaves to
give free play to the Italian Tarantula's legs. The Black-bellied
Tarantula's work takes the form of a well surmounted by its kerb.

When the soil is earthy and homogeneous, the architectural type is free
from obstructions and the Spider's dwelling is a cylindrical tube; but,
when the site is pebbly, the shape is modified according to the
exigencies of the digging. In the second case, the lair is often a
rough, winding cave, at intervals along whose inner wall stick blocks of
stone avoided in the process of excavation. Whether regular or
irregular, the house is plastered to a certain depth with a coat of silk,