Archive image from page 177 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 ( 178 AMERICAN SPIDERS AND THEIR SPINNINGWORK. Pig. 165. Spinning organs of Clubiona, showing the cribellum, cb. P, pos- terior ; m, middle; a, anterior spin- nerets; ca, calamistrura. (After Blackwall.) an old fashioned spinning wheel, and is apparently used to separate into a flossy mass the threads of silk as they issue from the
Archive image from page 177 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 ( 178 AMERICAN SPIDERS AND THEIR SPINNINGWORK. Pig. 165. Spinning organs of Clubiona, showing the cribellum, cb. P, pos- terior ; m, middle; a, anterior spin- nerets; ca, calamistrura. (After Blackwall.) an old fashioned spinning wheel, and is apparently used to separate into a flossy mass the threads of silk as they issue from the spinning glands. Bertkau, in an article on the cribellum and calamistrum, has shown cer- tain secreting glands at the ends of the fine tubes which have tlieir outlets in the former organ. It is not improbable, in view of this dis- coveiy, that the viscidity of the flocculent spirals of Uloborus and other spiders possessing this organ is caused in some measure by a slight secretion from these glands. It is the possession of cribellum and cala- mistrum by Uloborus and Hyptiotes which has led various arachnologists to separate Calamis- jg genera from the Orbweavers. Cribellum '''I'rton, for example, following Black- wall, Keyserling, and Bertkau, assigns them to the Clubionidse. Without entering at length into the reasons, based upon structure, for dissenting from this opinion, I have felt con- strained, on the grounds of their spinningwork alone, to place both these genera among the Orbitelariaj, where indeed such a distinguished systematic arachnologist as Professor Thorell has already l)laced them, and continues to keep them, notwithstanding all tlie objec- tions that have been advanced by the able naturalists who have esjioused the other view. Mr. Emerton has made some studies of the web of Uloborus Walck- enaerius, the common species of Northern Europe. I reproduce his figure (Fig. 167), which represents an unfinished web of this species seen in France. It shows the central
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