. 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. THE SPINNING ORGANS. 37 The spinnerets articulate obliquely from the outer side and the front, inward and backward, so that their tips approximate the correspond- ing spinning fields of the mid- dle spinnerets. The base is covered on both of its side faces with many rows of bris- tles (Fig. 25, b); it is divided from the terminal field by a suture, su, and a brown chit- inous zone, z. The terminal joint is cap-shape, and is onl
. 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. THE SPINNING ORGANS. 37 The spinnerets articulate obliquely from the outer side and the front, inward and backward, so that their tips approximate the correspond- ing spinning fields of the mid- dle spinnerets. The base is covered on both of its side faces with many rows of bris- tles (Fig. 25, b); it is divided from the terminal field by a suture, su, and a brown chit- inous zone, z. The terminal joint is cap-shape, and is only partially occuijied as a spin- ning field. On the top of the spinning field are from sixty to seventy very short spinning spools, , and a spinning spigot, connected with a cylindrical gland. Fig. 25, The base of these spigots is surrounded by a pair of chitinized stripes, which originate in the chit- inous zone, z. Close to this place is inserted a very strong and long sinew, sw, which unites with the chitinous border of the spin- ning field at the furrow (su) between the base and the terminal joint. This sinew passes beyond the root of the spinneret into the strong, motor muscle, ms, which controls the movement of the spinneret towards its fellows. Within the bases of the spinnerets are bundles of muscles which contribute both to the general move- ment of the spinneret and to the movement of the individual spools on the tip. On the chitinous edge of the spinning field is a single row of strong bristles, br. On examining the spinnerets with a lens of ordinary power, the tips or spinning fields are found to be covered with a great number of fine movable spinning tubes, already men- r—u-r^Ti^^^^S; ti^'^^d' k"«^'" '^^ «P"^"i"g «P««1« (Fig. 26), bj, basal joint. whicli are regularly disposed over the Fio. 25. Anterior spinneret, magnified largely, z, brown chit- inous zone that bounds the spinning field; sw, sinew of the bendin
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectspiders, bookyear1889
