top carefully counterfeits the surrounding ground. 2. The door
with silken hinge, held open by a needle. 3. The spider in its
doorway, looking for prey. 4. Section of the burrow and trap-
door.]

"The study of a number of specimens of our southern California
species, which builds the cork-type door, including observations
of them at night, when they are particularly active, indicates
that the construction of the tube involves other material than the
silken lining employed by many burrowing spiders. In the
excavation of the tube and retention of the walls, the spider
appears to employ a glairy substance, which thoroughly saturates
the soil and renders the interior of the tube of almost cement-
like hardness. It is then plastered with a thick jet of silk from
the spinning glands. This interior finishing process appears to
be quite rapid, a burrow being readily lined within a couple of
hours.

"The construction of the trap-door is a far more complicated
process, this convex, beautifully bevelled entrance with its hinge
requiring real scientific skill. Judging from observations on a
number of specimens, the work is done from the outside, the spider
first spinning a net-like covering over the mouth of the tube.
This is thickened by weaving the body over the net, each motion
leaving a smoky trail of silk. Earth is then shoveled into the
covering, the spider carefully pushing the particles toward the
centre, which soon sags, and assumes the proper curvature, and
automatically moulds against the bevelled walls of the tube.

"The shoveling process must be nicely regulated to produce the