Page:Popular Science Monthly Volume 37.djvu/53

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THE STRENGTH OF SPIDERS AND SPIDER-WEBS.

for a period of more than three years! How much longer it might have faithfully performed the same service I know not, as it then became necessary to break this admirable bond, to make some changes in the clock. Here it will be seen that the same web was expanded and contracted each second during the whole period, and yet never, so far as could be observed, lost any portion of its elasticity."

At various times there have been placed on record accounts of the capture by spiders of small vertebrate animals, as snakes, mice, and birds. Popular stories to the same effect have from time to time been sent the rounds of the daily press, and found utterance and often illustration, the latter sometimes of a most original and remarkable character, in popular magazine literature. The great seeming disparity, in such cases, between the size and vigor of captive and prisoner; the confusion of the various narratives in details as to the species and behavior of the spider, and the characteristics of her snare; the radical departure from known food habit of species that are insectivorous; together with the fact that the accounts all have come from lay observers, have been more or less lacking in scientific accuracy and minuteness of detail, and wholly without scientific verification—these considerations have caused such records and reports to be discredited by arachnologists and naturalists generally. But there are a few cases, confirmed by circumstantial evidence, and reported by observers of good reputation and careful habit, which deserve notice.

The physical powers of the Lycosidæ, the popular running, ground, or wolf spiders, are well illustrated by an instance recorded in the proceedings of the Academy of Natural Sciences of Philadelphia. The result as reported was achieved by pure strength and activity, without any of the mechanical advantages of a snare. Mr. Spring, while walking with a friend in a swampy wood, which was pierced by a dike three feet wide, was attracted by the extraordinary movements of a large black spider in the middle of a ditch. Closer examination showed that the creature had caught a fish! She had fastened upon it with a deadly grip just on the forward side of the dorsal fin, and the poor fish was swimming round and round slowly, or twisting its body as if in pain (Fig. 2). The head of its black enemy was sometimes almost pulled under water, but the strength of the fish would not permit an entire submersion. It moved its fins as if exhausted, and often rested. Finally it swam under a floating leaf near the shore and made a vain effort to dislodge the spider by scraping against the under side of the leaf.

The two had now closely approached the bank. Suddenly the long black legs of the spider emerged from the water, and the hinder ones reached out and fastened upon the irregularities of