. The biology of spiders. Spiders; Insects. 4° THE BIOLOGY OF SPIDERS sex seems to exert an influence, the number of teeth increasing in male spiders and decreasing in females. Finally, there is a type of structure known as accessory claws present on the tarsi and also on the spinnerets of orb-weaving or Epeirid spiders. These are straight and spine-like, but their lower edge is notched with a few small teeth. The Spinnerets The only abdominal appendages persistent in the adult spider are those of the fourth and fifth segments, where they function as the spinning organs—namely, the cribellum,
. The biology of spiders. Spiders; Insects. 4° THE BIOLOGY OF SPIDERS sex seems to exert an influence, the number of teeth increasing in male spiders and decreasing in females. Finally, there is a type of structure known as accessory claws present on the tarsi and also on the spinnerets of orb-weaving or Epeirid spiders. These are straight and spine-like, but their lower edge is notched with a few small teeth. The Spinnerets The only abdominal appendages persistent in the adult spider are those of the fourth and fifth segments, where they function as the spinning organs—namely, the cribellum, where this organ is present, and the six spinnerets. The cribellum represents the endopodites of the fourth segment, whose exopodites are the anterior or superior spinnerets. The small middle spinnerets are the endopodites of the fifth, and the exopodites of this segment are the posterior or. Fig. 26.—Spinnerets of Hahnia. inferior spinnerets. The number of spinnerets differs, however, from type to type. In the Liphistiomorphae, the primitive number, eight, is found, occupying the middle of the lower surface, but only the four exopodites are said to be active. In most Mygalomorphae there are four spinnerets, the anterior and median pairs, and in exceptional instances the spinnerets number only two—sometimes the two anterior and sometimes the two posterior. In most spiders, the spinnerets when at rest form an inconspicuous group at the end of the abdomen and the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Savory, Theodore Horace, 1896-. London : Sidgwick & Jackson
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecti, booksubjectspiders
