structed, the mason stretches a little web over the opening, sticking to it such particles of earth as it may find within its reach. A new sheet of silk is stretched over this, and a second layer is formed; and the process is repeated till the trap-door has obtained the requisite thickness. Then it shaves the edges to make the contours even, and the door is finished. If we compare several nests of the same species, we shall notice considerable differences in the merit of the work, from the greatest excellence down to comparative inferiority. Sometimes we find nests with two doors and two vestibules. In the majority of instances of this kind, one of the trap-doors has been condemned. Sometimes the hole is provided with an ascending annex, not opening out upon the surface but provided with an interior door separating a smaller chamber from the main abode. This puts the spider to advantage against an enemy that may have gained access to the main chamber. The ctenizas take a variety of precautions against being discovered. Sometimes the trap-doors are disguised by looking in no way different from the ground around them. In other places they are concealed by means of moss, lichen, grass-blades, bits of straw, or whatever foreign bodies it may be convenient to strew around and over them. The masons are very diligent in their work. If one of them is deprived of his retreat, he will replace it in a night or two. But, notwithstanding their skill in construction, the best observers affirm that young spiders will not abandon a nest when it has become too narrow for them. They have the art of enlarging them so that they shall always be at ease within. The Austrian naturalist, Erber, met in the island of Tinos, in 1868, a previously unknown species. He studied its habits and found that it came out of its nest every evening to make an excursion, but left its door open, fastening it back to some stone or plant-stalk, protecting the entrance by weaving over it a net which it destroyed on its return in the morning.
The trap-door spiders have been seen in many parts of the globe, but usually in countries where a high temperature prevails. They are abundant in the countries around the Mediterranean, and have been observed in the Austral lands and in America. A species of very fair proportions, the Cteniza Californica, lives in California. A living specimen was kept and observed by M. Hippolyte Lucas for four months in the Muséum d'Histoire naturelle. The observer succeeded in opening the door of the cell and presenting the spider with a fly. The cteniza, hungry after a long voyage, seized the fly at the entrance of its burrow, but retired to the back upon the attempt being made to draw it out; and it continued suspicious, even toward its friend. One night, after it had had a few days of good feeding, it sealed the circumference of its
