=Spider-Webs.=—Some account has already been given of the external and internal spinning organs of Spiders. Within the body of the animal the silk is in the form of a gummy fluid; and this, being emitted in exceedingly fine streams, solidifies as it meets the air. It cannot be shot out to any distance, but the animal usually draws it out by its hind legs, or attaches it to a spot, and moves away by walking or allowing itself to drop. It has some power of checking the output, and can stop at will at any point of its descent; but the sphincter muscles of the apertures are but weak, and by steady winding the writer has reeled out a hundred yards of the silk, the flow of which was only then interrupted by the spider rubbing its spinnerets together and breaking the thread. There is, of course, no true spinning or interweaving of threads in the process, but parallel silken lines are produced, varying in number according to the special purpose for which they are designed, and sometimes adhering more or less to one another on account of their viscidity and closeness. The silk is utilised in many ways, serving for the construction of snares, nests, and cocoons, as well as for enwrapping the captured prey, and for anchoring the spider to a spot to which it may wish to return. Spiders may be roughly distinguished as sedentary or vagabond, the former constructing snares, and the latter chasing their prey in the open. We will first consider the various forms of snare, beginning with that characteristic of the Epeiridae. =The Circular Snare.=—This familiar object, sometimes spoken of as the orb-web or wheel-web, is always the work of some spider of the Family Epeiridae. The accuracy and regularity of form exhibited by these snares has caused their architects to be sometimes called the _geometric_ spiders. The ingenuity displayed by them has always excited the admiration of the naturalist, and this is increased on closer observation, for the snares are in reality even more complex than they appear at first sight. The first care of the spider is to lay down the foundation threads which are to form the boundary lines of its net. If the animal can reach the necessary points of attachment by walking along intervening surfaces the matter is comparatively simple. The spinnerets are separated and rubbed against one of the points selected, and the spider walks away, trailing behind it a thread which it keeps free from neighbouring objects by the action of one of its hind legs. On reaching another desirable point of attachment the line is made taut and fixed by again rubbing the spinnerets against it. By a repetition of this proceeding a framework is presently constructed, within which the wheel or orb will ultimately be formed.