Page:Harvesting ants and trap-door spiders. Notes and observations on their habits and dwellings (IA harvestingantstr00mogg).pdf/170

 It seems to be the rule with spiders generally that the offspring should leave the nest and construct dwellings for themselves when very young.

Mr. Blackwall, speaking of British spiders, says:—"Complicated as the processes are by which these symmetrical nets are produced, nevertheless young spiders, acting under the influence of instinctive impulse, display, even in their first attempts to fabricate them, as consummate skill as the most experienced individuals."

Again, Mr. F. Pollock relates of the young of Epeira aurelia, which he observed in Madeira, that when seven weeks old they made a web the size of a penny, and that these nets have the same beautiful symmetry as those of the full-grown spider. Those of the latter are vertical, circular, made of about 250 feet of thread, having about 35 radial lines and 38 concentric circles, the outermost of which is some 20 inches in diameter. After the lapse of a day or two the web loses its adhesive property and a new one is made. In about six months the female Epeira has completed her ten changes of skin, one of which takes place in the cocoon, and "at the end of eight months the spider is 2700 times as heavy as at its birth." This Epeira lives, we are told, for about eighteen months.

One can scarcely contemplate the work of these architects and weavers, and especially of the trap-door makers, without being carried away into the whirlpool of discussion which has so long raged round the word instinct.