Page:Popular Science Monthly Volume 33.djvu/816

796 which is composed of many genera (Fig. 7); but the family is one of which the members are all so alike that they all bear the same general signs and pursue the same kind of industry. The epeïras weave webs of enormous proportions, with large, regular meshes. As they work in broad daylight, among the most beautiful features of nature, it is possible to follow them in all their operations, which are performed as if expressly to charm a philosopher. The spectacle may be witnessed every summer in the parks and gardens of Paris in the webs of the Epeïra diadema, which sometimes obstruct the streets. This spider is of a reddish-yellow color, marked on the upper part in dark hues with a figure that has been compared with the cross of St. Denis. Posted on a branch of privet, lilac, or cytissus, it puts forth a thread of silk which lengthens out under the very eye of the observer, and, caught up by the lightest breath of air, at last fastens itself to the limb of a shrub, often at a considerable distance from the point of departure. Subsequently the spinner herself mounts the aërial cord, and fastens it to the place where it has fixed itself, adjusting its position if necessary. The most skilled balancers in the circus would lose in the comparison with the epeïra of the gardens, which manoeuvres in every kind of attitude, upon a thread of extreme tenuity, with an ease and agility that defy all parallel. Threads carried to new points of support among the branches are adjusted so as to form a polygonal framework. This done, the spider returns upon the bridge which it first threw over, and stopping exactly in the middle, as if it had calculated the spot geometrically, it drops, head down, hanging to a thread which would divide the polygon in two. At the central point is fixed a fleck of silk that serves as a support to all the rays which diverge regularly to the periphery. The frame is made, but a final operation remains to be completed. An agglutinating thread must be stuck upon the rays, so as to form a spiral. The epeïra comes to the center of the web, draws the thread, which it attaches to the fleck of silk, and passes from ray to ray, describing circles away out to the exterior line of the frame. It will finish its work by returning from the circumference to the center, to interpose new circles between the former ones. It is impossible to realize a more sagacious combination to obtain a charming network, a lace of more admirable perfection (Fig. 8). Accidents will happen to the web of the epeïra. Gusts of wind during storms, or the stroke of a bird's wing, may mar its usefulness. The skillful spinner is only slightly affected by a disaster of the kind, for in less than an hour it will construct a new network. It is in cases where the web has suffered a single tear that