This single experiment has been here described in some detail largely for the purpose of impressing the reader with the importance of reducing the problem to its simplest terms before any inferences are drawn, and it may well act as a model for any which he may be inclined to undertake on his own account. The more complicated the action, the more likely is the experimenter to read into it motives and mental operations which exist only in his own imagination, and with this warning we must take leave of a subject which might tempt us to encroach too much on an allotted space. CHAPTER V TRAP-SNARES AND BALLOONS There are some interesting variants of the circular snare spun by some exotic Epeirids. One North American species spins it in a horizontal position and then raises the centre, and, by an elaborate system of stay lines from above, converts it into a very accurately shaped dome. A whole group of orb-weavers habitually decorate a sector of the snare with bands of flocculent silk, the object of which for a long time puzzled arachnologists, till it was observed that the spider drew upon this reserve supply of material to wrap up particularly obstreperous insects. It is not unusual for a spider of one of the common species to remove a whole sector of the snare, and by stretching a line from the centre to a place of retreat along the gap thus formed, to provide an unencumbered avenue between its home and its post when on duty. For it must not be forgotten that a spider has to walk warily on its own web, and must avoid, as far as possible, treading on the adhesive lines, or delay and damage to the structure are sure to ensue. As a rule the circular snares of the different British species are of a very uniform pattern, differing chiefly in the degree of neatness with which they are constructed, and in certain minor details of the “hub,” but we have one spider, _Hyptiotes paradoxus_—an exceedingly rare species, scarcely ever seen beyond the limits of the New Forest—which makes such a strange snare that it seems a pity to omit all mention of it. It consists of a sector—about one sixth of the full circle—comprising about four radii with cross lines. From the point where the radii meet, a “trap-line” connects the sector to another point of attachment; on, or rather under, this trap-line, the spider takes up its position, hauling it in so as to tighten the web and to leave a slack portion of the line between the points where it holds on by its front and hind legs. When an insect impinges on the web and causes it to tremble, the spider immediately lets go with its fore legs, and the consequent vibration of the web helps to entangle its prey.