Rensselaer Union, Volume 7, Number 6, Rensselaer, Jasper County, 29 October 1874 — The Net of the Garden Spider. [ARTICLE]

The Net of the Garden Spider.

The web or net of the common garden spider, Epeira diadema, may be seen in every garden, spread across little openings between the branches and canes of fruit trees, bushes and vines. It is more abundant this year than for several years past. It is generally passed by without any regard or concern, yet its fabricator is useful in destroying some of the moths and flies that produce injurious larvae. R has been discovered that the net of this spider consists of two kinds of silk. The threads of the concentric circle are composed of silk much more elastic than that of the rays, and are studded over with minute globules of a viscid gum, sufficiently adhesive to retain any unwary fly that comes in contact with it. A net of average dimensions has been found to contain 87,363 of these globules, and a large net, fourteen or sixteen inches in diameter, 120,000; yet this net will be completed in about forty minutes if no interruption occur. In'ordinary circumstances the threads lose their viscidity by exposure to the air, and require to have it renewed every twenty-four hours. Any person by scattering a little fine dust over the w r ebs may satisfy himself that it is retained only on the circles where the minute globules are placed, and not upon the radii. If the globules are removed, both lines are unadhesive; but in other respects they are different, the circular lines being transparent and highly elastic, while the radial lines are opaque, and possess only a moderate degree of electricity. Astronomers find the opaque silk of the radical lines and of the egg bag a convenient substitute for platina wires in the telescopes attached to their instruments, but the silk of the circular lines, being transparent, is unsuitable for this purpose.— Western Rural.