The most extraordinary nest, however, of the whole species, is that of the mason-spider, which is a native of the tropics, and is generally found in the West Indies. This nest is formed of very hard clay, colored deeply with brown oxide of iron. It is constructed in the form of a tube, about one inch in diameter and six or seven long. Their first labor is to line it, which they do with a uniform tapestry of orange-colored silken web, of a texture rather thicker than fine paper. This lining is useful for two important purposes: it prevents the walls of the house from falling down, and also, by being connected with the door, it enables the spider to know what is going on above, for the entire vibrates when one part is touched. Our readers who have not been so fortunate as to meet with this description of nest, may very probably feel inclined to laugh at our mention of a door. It is nevertheless perfectly true that there _is_ a door, and a most ingeniously contrived one also, and truly it may be regarded as one of the most curious things in the whole range of insect architecture. It is about the size and shape of a crown-piece, slightly convex inside, and concave on the outer side. It is composed of twelve or more layers of web, similar to that with which the inner part is lined; these are laid very closely one over the other, and managed so that the inner layers are the broadest, the others gradually diminishing in size, except near the hinge, which is about an inch long; and as all the layers are united there, and prolonged into the tube, it is necessarily the firmest and strongest portion of the entire structure. The materials are so elastic, that the hinge shuts as if it had a spring, and of its own accord. The hole in which the nest is made being on a sloping bank, one side must always be higher than the other, and it is observed that the hinge is invariably placed on the highest side, because the spider knows well, that, when so situated, the door, if pushed from the outside, will fall down by its own weight, and close; and so nicely does it fit into the little groove prepared for it, that the most attentive observer could scarcely discover where the joining was. In this safe retreat the wary spider lives, nor will the loudest knocking tempt it out of its hiding-place. Should, however, the least attempt be made to force open the door, the spider, aware of what is going on by the motion of the threads, runs quickly to the door, fastens its legs to the silk lining of the walls, and, turning on its back, pulls the door with all its might. The truth of this assertion has been tested by many entomologists, who, by lifting the door with a pin, have felt the little spider trying to prevent their entrance; the contest, of course, is not a long one, and the assailants being uniformly victorious, the spider seeks safety in flight. Should the door be entirely taken away, another will soon be put in its place. These spiders hunt their prey at night,