Another genus, which lives in warm countries, makes tubes lined with silk, and closed at the top by a trap-door. A common species, Cteniza Californica, lives in the southern part of California, and is often brought east by travellers. It digs its hole in a fine soil, that becomes, when dry, nearly as hard as a brick; but the spider probably works when the ground is wet. The holes are sometimes nearly an inch in diameter, and vary in depth from two or three inches to a foot. The mouth is a little enlarged, and closed by a thick cover that fits tightly into it, like a cork into a bottle. The cover is made of dirt fastened together with threads, and is lined, like the tube, with silk, and fastened by a thick hinge of silk at one side, [Fig. 22], B. When the cover is closed, it looks exactly like the ground around it. The spider holds on the inside of the door with the mandibles and the two front pairs of feet; while the third and fourth pairs of legs are pressed out against the walls of the tube, and hold the spider down so firmly, that it is impossible to raise the cover without tearing it.

Among the trap-door spiders of Southern Europe, about which Mr. J. T. Moggridge has written a very interesting book, are species which make different kinds of nests. The cover, instead of being thick, and wedged into the top of the tube like a stopper, is thin, and rests on the top of the hole, [Fig. 22], C, and is covered with leaves, moss, or whatever happens to be lying about; so that it is not easily seen. Two or three inches down the tube is another door, [Fig. 22], E, hanging to one side of the tube when not in use; but, when one tries to dig the spider out from above, she pushes up the lower door, so that it looks as if it were the bottom of an empty tube.

Another species digs a branch obliquely upward from the middle of the tube, closed at the junction by a hanging-door, which, when pushed upward, can also be used to close the main tube, [Fig. 22], F. What use the spider makes of such a complicated nest, nobody knows from observation; but Mr. Moggridge supposes that when an enemy, a parasitic fly, for instance, comes into the mouth of the tube, the spider stops up the passage by pressing up against the lower door; but, if this is not enough, it dodges into the branch, draws the door to behind it, and leaves the intruder to amuse himself in the empty tube. The branch is sometimes carried up to the surface, where it is closed only by a few threads; so that, in case of siege, the spider could escape, and leave the whole nest to the enemy.

Fig. 22.

In these nests the spiders live most of the time, coming out at night, and some species in the daytime, to catch insects, which they carry into the tube, and eat. The eggs are laid in the tube; and the young are hatched, and live there till able to go alone, when they go out, and dig little holes of their own. As the spider gets larger, the hole is made wider, and the cover enlarged by adding a layer of earth and silk; so that an old cover is made up of a number of layers, one over the other, over the original little cover.

Moggridge once took a Cteniza Californica out of her nest, and put her on a pot of earth, and the next morning had the good luck to see her at work digging. She loosened the earth with her mandibles, and took it in little lumps with the mandibles and maxillæ, and carried it away piece by piece. It took her an hour to dig a hollow as large as half a walnut. He saw the making of the door twice by other species. Once he dug a hole for a spider in some earth, and the next day found her in it, and the top covered by a little web, on which were scattered bits of earth and leaves, which had evidently been put there by the spider. The second night, enough dirt and silk were added to make the door of the usual thickness; but the spider never finished it so that it would open properly on its hinge. Another time Moggridge saw at the mouth of a very small hole a spider at work making a door. She spun a few threads across the hole, then gathered up with her front-legs and palpi an armful of dirt, and laid it on top of them. She then got under the pile, into the tube; but the motions of the dirt showed that she was still at work on it, and next morning the under side had been thickly covered with web, and the whole separated from the mouth of the tube, except at one side, where the usual hinge was left. The new door was at first soft, but in two or three days hardened, and appeared exactly like an old door.

These spiders are accustomed to put on the door moss like that which grows around it, and so conceal the door from sight; but when Mr. Moggridge took away the moss, and dug up the ground around a hole, and then destroyed the cover, the spider made a new one, and brought moss from a distance to put on it, thereby making it the most conspicuous thing in the neighborhood.