web, out of which all intruders were kept. And now it was found that all these webs were inclined at nearly the same angle, and were never exactly vertical; that, like the spider in the first web she made in the Botanical Garden, the insect took a position much nearer the upper than the lower border; and also that, instead of a web of perfect circles laid upon regular radii, as used to be described and is still figured in our books, or even one of a spiral line, as is now more correctly described of ordinary geometrical spiders (Fig. 6), these never made a circle, nor even a spiral, but a series of concentric loops or arcs of circles, the lines turning back upon themselves before reaching a point over the spider, and leaving the larger portion of the web below her; and more than this, that the lines, though quite regular, were by no means perfectly so, as may be seen in Fig. 7, copied from a photograph.
Fig. 6. Web of common Garden Spider.
Fig. 8. Section of Web.As usual, the radii, or spokes, of the wheel-shaped structure are first made; then the spider begins a little way from the centre, and, passing from one radius to another, spins a series of loops at considerable distances from each other till she reaches the circumference. These first loops, like the radii, are of white, dry, and inelastic silk, and may be recognized by the little notches at their junction with the radii. The notches are made by the spider's drawing her body a little inward toward the centre of the web at the time of attaching them to the radii, and so they always point in the direction in which the spider is moving at that time, and in opposite directions on any two successive lines (Fig. 8). Having reached what is to be the border of her web, and thus constructed a firm framework or scaffolding, she begins to retrace her steps, moving more slowly and spinning now in the intervals of the dry loops two or three similar loops, but much nearer together and made of the elastic and viscid silk, till she has again reached her starting-point near the middle of the web, where, on its under side, she takes a position, head downward, hanging by her claws, and thus keeping her body from direct contact with the web.
Fig. 7. Web of Nephila plumipes.
