. The biology of spiders. Spiders; Insects. 42 THE BIOLOGY OF SPIDERS These are scattered in large though variable numbers over the fields of all spinnerets. They have two uses. Those on the anterior spinnerets produce the little band or transverse sweep of many tiny threads which anchor a spider's lines to the ground, and are known as attachment discs ; while those on the other spinnerets provide the much broader ribbon which the spider wraps round its resisting victim. The larger tubes, or spigots, are conical in shape and more constant in number and position Their complete. Fig. 27.—Spinnin
. The biology of spiders. Spiders; Insects. 42 THE BIOLOGY OF SPIDERS These are scattered in large though variable numbers over the fields of all spinnerets. They have two uses. Those on the anterior spinnerets produce the little band or transverse sweep of many tiny threads which anchor a spider's lines to the ground, and are known as attachment discs ; while those on the other spinnerets provide the much broader ribbon which the spider wraps round its resisting victim. The larger tubes, or spigots, are conical in shape and more constant in number and position Their complete. Fig. 27.—Spinning-tubes or Spigots. A, Of cylindrica gland of Tegenaria. B, Of ampullaceal gland of Epeira. C, Of aciniform gland of Epeira. (B, after Apstein.) distribution among all or even most of the families does not seem to have been worked out, but Warburton (1895) has made a careful study of them in the case of the highest type of spinners, the orb-weavers, Epeiridae, and his results are summarised below. The inferior, median and posterior spinnerets of Epeira carry respectively one, three and five spigots each. Those on the anterior spinnerets and one of those on each median spinneret provide the foundation lines of the web and the drag-line which many spiders lay down behind them. 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
