. American spiders and their spinningwork. A natural history of the orbweaving spiders of the United States, with special regard to their industry and habits . n differs from this in having but a single de-tached radius (dr) to which cross loops (cl) pass from the marginal radiiR, R. (Fig. 129.) When weav-ing in the spirals this spider doesnot pass entirely around the orb,as is the case with the full orbmakers in the major part of theirsnare, but moves back and forthbetween the radial borders (, c and d) of the open sector,spinning her spirals in successivehorseshoe loops. This T is the
. American spiders and their spinningwork. A natural history of the orbweaving spiders of the United States, with special regard to their industry and habits . n differs from this in having but a single de-tached radius (dr) to which cross loops (cl) pass from the marginal radiiR, R. (Fig. 129.) When weav-ing in the spirals this spider doesnot pass entirely around the orb,as is the case with the full orbmakers in the major part of theirsnare, but moves back and forthbetween the radial borders (, c and d) of the open sector,spinning her spirals in successivehorseshoe loops. This T is the method observed Lioops. by Zilla, and all sectoral orb makers in fact. The for itis at once apparent. Of course, in this case the term spiral has onlya technical application to these lines. (Fig. 130.) The number of both spirals and radii varies greatly. The latter aremore numerous, often far more numerous below than above the hub,which frequently is situated well above the geometric centre of the , in an orb six inches wide by seven long the spirals in the upperjjart of the snare numbered nineteen, in the lower thirty-two. The lower. Fig. 127. Fig. 128. Fig. 129. Variations in the open sector; detached radii. 140 AMERICAN SPIDEUS AND THEIK SlINNINCiWdlUv. Spirals wcri tlius drawn in sliortri loops uitli niucli less ciuvc, ami the centre of the huh was well toward the toj), two inches therefrom. In an- otiier adult weh the orb measured eleven inches long by eight wide, tlie nvunljii of Iadii was forty-one, of spirals forty-five, of notched concentrics nine. The centre of the hul) was five inches from the topmcst sjural. The following measurements give some idea of the size of Tri- ^^^ araneas orb: Web No. 1, about four inches diameter; radii . forty-three; spirals thirty-five. No. 2, radii twenty; spirals twenty. No. 3, diameter six and a half inches; radii thirty-five; spirals thirty-five. No. 4, seven inches long by six wide. No. T), six and a half long by
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Keywords: ., bookcentury1800, bookdecade1880, bookidamericanspid, bookyear1889
