. American spiders and their spinning work. A natural history of the orbweaving spiders of the United States, with special regard to their industry and habits. Spiders. 76 AMERICAN SPIDERS AND THEIR SriNNIN(JWORK. passed down 1 and along D to 3, where attachment was made, and radius 3 was formed. Once more the centre was sought, and passing along the line A the point 4 was reached and another radius there fastened. Thus on from 4 to 5, from 5 to 6, and so around tlie entire circle. The mechan- ical advantage of this order is api)arent. Several times the central termini of the radii were streng
. American spiders and their spinning work. A natural history of the orbweaving spiders of the United States, with special regard to their industry and habits. Spiders. 76 AMERICAN SPIDERS AND THEIR SriNNIN(JWORK. passed down 1 and along D to 3, where attachment was made, and radius 3 was formed. Once more the centre was sought, and passing along the line A the point 4 was reached and another radius there fastened. Thus on from 4 to 5, from 5 to 6, and so around tlie entire circle. The mechan- ical advantage of this order is api)arent. Several times the central termini of the radii were strengthened by lapping threads across them. This tendency to alternate apposition I have frequently observed in various species, and its character will be better shown by giving several other schemes of the order of progression in spinning radii. The r er o schemes do not present a complete sequence of the radii from the very beginning, but number from the point at which I hap- pened to catch the spider at work. They are to be read as in Fig. 72, the order of numerals showing the relative position of the radial lines in the order of their spinning. The series will show, I tliink, that M'hile no abso- lute mathematical regularity marks the succession, some method of alterna- tion evidently dominates the spider's movements. She knows the necessity. Fig. 74. Order of inserting nine radii. Fig. 75. Ordcrof six radii. Order of five radii. Fig. 73. Theorder of spinning in twelve radii. Epeira ver- tebrata. which exists for balancing such a peculiar and delicate structure, and adopts her mode of spinning to the exigencies of her spinningwork. Blackwall states that after the completion of the radii the si)idcr pro- ceeds to the centre, turns around and pulls each radius with her feet to ascertain its strength, breaking such as are defective, and replacing them by others. I have never seen anything of the kind; the spider in settling herself and gathering the radial lines into her e
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectspiders, bookyear1889
