Indeed, it could require no very great consideration to decide, that spiders’ silk, when compared with that of the silkworm, was vastly inferior for manufacturing purposes, though employed in many useful and highly ingenious ways by the insect itself. A few of these we must not omit to notice. Every one must have seen the common garden spider (_Epeira diadema_) suspended by its silken rope, or forming its beautiful web; but every one is not aware that that silken rope is made up of a multiplicity of threads, and that when the spider attaches the rope to any object by pressing her spinneret against it, she spreads out these threads over an area of some diameter, thus securing a much greater degree of strength than could be gained by merely fixing her thread to one point. This contrivance may be seen best when the threads are attached to a black object. Under the microscope they appear thus:— [Illustration: SPIDER’S METHOD OF ATTACHING HER THREAD. ] The uses of silk in the webs and nests of common spiders are too obvious to be dwelt on, but there is a most clever and surprising adaptation of the same material by several foreign species of spider which must be briefly stated. In the Ionian islands, and also in the West Indies, there are found certain spiders, commonly known as trap-door spiders, which make a cylindrical nest in the earth, and cover the entrance with a door of their own construction, framed of alternate layers of silk and earth, and fastened to the opening by a hinge of stout silk. These spiders also line their nests throughout with numerous layers of silken web to the thickness of stout cartridge paper, and finish it with the greatest care. This beautiful lining is yet further strengthened in particular parts, where the nest is likely to be exposed to danger. But the greatest amount of skill and care is bestowed upon the trap-door and its silken hinge. This door is about the eighth of an inch thick, rough on the outside, not much unlike an oyster shell, which it also resembles in being thick and strong near the hinge, but thinner towards the circumference. The breadth of this hinge is various, but sometimes it is very considerable, as shown in the accompanying figure. It also possesses great elastic force, so that on being opened, it closes again of itself. This is principally accomplished by a fold or doubling of the web, at each end of the hinge, which permits the door to be opened nearly to a right angle with the aperture, but no farther, unless violence be used. The under side of the door is perfectly smooth and firm, being shaped so as to fit accurately, and yet to offer no resistance when pushed open by the insect. [Illustration: TRAP-DOOR SPIDER. ] [Illustration: NEST OF TRAP-DOOR SPIDER. ] [Illustration: TRAP-DOOR OPENING BY A LEVER. ]