Archive image from page 46 of American spiders and their spinning. 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 CUbiodiversity1121211-9742 Year: 1889 ( THE SPINNING ORGANS. 47 Somewhat different from the above are the spinning spools which are found on the anterior spinnerets. On these (Fig. 40) the bases consist of a short, more conical segment, which diminishes considerably from the broader base toward the free end. This conical basal joint, bj, is provided with a strongly concave
Archive image from page 46 of American spiders and their spinning. 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 CUbiodiversity1121211-9742 Year: 1889 ( THE SPINNING ORGANS. 47 Somewhat different from the above are the spinning spools which are found on the anterior spinnerets. On these (Fig. 40) the bases consist of a short, more conical segment, which diminishes considerably from the broader base toward the free end. This conical basal joint, bj, is provided with a strongly concave end space. The terminal joint is almost double the length of the base, and is not straight as in the spools of the pos- terior spinnerets, but is a little curved. It stands in the centre of the concave end space of the basal cylinder. Dispersed among these smaller spools of the pyriform glands are shorter and thicker spools, sp, through which discharge the cylindrical and treeform glands, Fig. 35. Those belonging to the cylin- g J drical glands differ from those of the treeform glands in the character of the end space, which is in the former longer and considerably thicker. In general, however, the construction of all these formations ii similar. Figure 41 shows the discharging spigot of a cylin- drical gland, situated at the tip of the middle spinneret. This spigot like spinning tube consists of a basal piece, bj, formed by brown chitinous walls and a cylindrical end piece, tj, which tapers more sharply towards the point. . u r, . We are now better prepared to consider these beautiful V\.| r'/ instruments in their relation to their several silk glands. Close by the lower end of the spinning field of the pos- terior spinneret stands a large spool (Fig. 3, sp) into which leads a cylindrical gland. Farther above are the spools of two treeform glands, and close by are the two spools of two cylindrical' glands. Besides these, innumerable spools of the ''' aemato '' pyriform glands
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