. 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-erally closed (Fig. 21), forming asort of rosette of five divisions; butwhen the spider is engaged in ac-tive operations, the posterior andanterior spinnerets are thrown well back, and the two middle1. Poste- QQgg Qpgj^ ^^p^ j^j-^j thus,nor P ^^ ^Q quote the language of Duges, this singular flow-er uirfolds. The posterior sjiinner-ets (Figs. 21 and 23, P)^ are wellseparated from each other, and liedirectly forward of the semilunaranal
. 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-erally closed (Fig. 21), forming asort of rosette of five divisions; butwhen the spider is engaged in ac-tive operations, the posterior andanterior spinnerets are thrown well back, and the two middle1. Poste- QQgg Qpgj^ ^^p^ j^j-^j thus,nor P ^^ ^Q quote the language of Duges, this singular flow-er uirfolds. The posterior sjiinner-ets (Figs. 21 and 23, P)^ are wellseparated from each other, and liedirectly forward of the semilunaranal covering (Fig. 21, ac). Theyare movable horizontally towardeach other, so that their long ovalspinning fields approximate and, indeed, may be said to lie ui)on the cor-responding middle spinnerets. They may be described as tluimb shapedorgans; are of a long, cylindrical form, and towards the free end are con-ically rounded. The terminal joint is divided from the base by a 23, su, which extends along the inner and hinder edge, much fartherthan on the opposite edge, so that the spinning field extends on that facemuch farther towards the Fig. 23. Posterior spinneret of Ep. diademata, greatlymagnified, su, sutine between joints; SP, spinningfield; bb, branched bristles; sb. simple bristles; sp,spigot spool; , long spinning spools; , shortspools. (After Bucholz and Landois.) 1 Meckel and Oeffinger both aUribute three joints to the posterior and anterior, and twoto the middle spinnerets. = To prevent confusion and the ninltiplication of references to figures the same letter-ing is preserved for like organs and parts thereof in all the anatomical figures. 30 AMKKICAN SlIDKltS AND THEIR SPINNINGWORK. Tlie spinning field, SF, is an elliptical slope, which is situated on theinner side of the spinneret, and extends across the summit to the oppositeface of the tip. Tlie basal part of the spinneret is cylindricalpP^J^^^^ and gradually grows smaller towa
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Keywords: ., bookcentury1800, bookdecade1880, bookidamericanspid, bookyear1889
