to overcome the downward pressure of the large lid; if the hole were perpendicular, the spider would have difficulty in levering herself over the edge against the weight of the lid, and, if the exit were not slanting and there were no flap, the loose, gritty sand would give way under her feet as she strove to get out. The little felt-like flap leads her gradually on to level ground, where she can easily make her way in any direction to the edge of the lid.
Secondly, the flap can, in case of necessity, serve as a make-shift door. If you tear the lid off and wait a little while, you will see the front legs of the spider emerge at A and pull at any fragment of hinge left, in order to close the hole temporarily; if she fails at this, she will pull up the flap, which, as I have said, is loose and just long enough to close and conceal the hole admirably. It is interesting to note that the spider always comes up facing A, which results in her being pretty well concealed while closing the hole; whereas, if she came up facing B, the slant would, to a considerable extent, expose her. This would seem to indicate that the flap is resorted to as a make-shift door only if the spider finds there is not enough web for the purpose left from the torn-off hinge.
Sometimes if you sit and watch an undisturbed nest, you will see the large 'butterfly' lid tremble, and then you will see the points of the little legs appear at the edge as the spider throws out the remains of a small ant or fly or some grains of sand. If you then quickly remove the lid, she will pop round and hide under it on the open ground. If exposed she lies perfectly still with her legs drawn in, feigning death, and may be handled like a dead thing. As she is very much the color of the loose sand, it is quite common to miss her, unless great care be taken.
It will be seen that this wonderful little spider is far ahead of the trap-door Lycosa in the complexity of her nest; but we have not yet reached the limit of her intelligence. Often she builds a beautifully webbed blind side-chamber, about half way down the hole, into which she escapes, and which, when the sand is disturbed, collapses over her and enfolds and hides her. I did not find the side chamber till I sought for it carefully. It is a late development, and shows she is no mere brilliant amateur like the Lycosa.
The trap-door eresid never, as far as I know, leaves the nest during the day, and certainly never opens the door, but creeps in and out under it, thus always leaving it closed. Neither do the adult males make doors or live under ground. Digging shows females, adult and young in the nests, but males only up to the last molt.
Here again comes a new and very interesting departure on the part of the eresid. The male, which, for all practical purposes, is,
