. 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. 74 AMERICAN SPIDEKS AND TIIEIK Sl' 89. Spinning tlie initial iiulii The trapezoidal foundation lines, xâx, are woven within the basilar part of the triangle thus formed. We have here the usual Foundation Space, FS, and indeed might aptly apply that term to the entire Founda- tion system. But it will be convenient, in webs of this form, to name the inner side of the trapezoid, IFL, the Inner Foundation Ijines, and th
. 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. 74 AMERICAN SPIDEKS AND TIIEIK Sl' 89. Spinning tlie initial iiulii The trapezoidal foundation lines, xâx, are woven within the basilar part of the triangle thus formed. We have here the usual Foundation Space, FS, and indeed might aptly apply that term to the entire Founda- tion system. But it will be convenient, in webs of this form, to name the inner side of the trapezoid, IFL, the Inner Foundation Ijines, and the large exterior cords, ab, cd, the Outer Foun- dation Lines, and the intermediate space, OFS, the Outer Foundation Space. The inner foundation lines are of course necessary to the construction of the orb under such circumstances, but ^®°. "'they are plainly so adiusted as ner Lines. â¢' 'â â¢' â '. not only to allow the nicest bal- ance of the beautiful snare, but also to afford the greatest power of resistance by distributing the disturbing forces of wind and struggling entangled insects along the elastic inner foundation lines. Webs of this character have less rigidity and would seem to be bettor designed to endure, than those which are directly attached to limbs and foliage. A foundation having bopn secured, the spider proceeds to place in the radii. To this end a position is taken at or near the centre of the orb, usually by dropping down from a toj) line, dragging ^^'l^'^^.'^.'^after her a thread which becomes the initial radius, Fig. (iO, a. ' At the central terminus of this radius a little ball of floss (11) is formed by emitting a thick ray of silk or by gathering together into a wad the many tentative lines with which the space within the frame is frequently matted. This ball evidently serves as an anchorage for the radii and perhaps also as a guidon for the animal herself. Sometimes as the work pro- ceeds and the strain of the new laid radii is felt
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectspiders, bookyear1889
