. 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 SENSES AND TITEIR ORGANS. 297 time when, having deposited the eggs within the little circular patch, she rolls the cover around thein into a ball, and then attaches the ball to her spinnerets. This is undoubtedly the universal method with spiders that carry about their egg sacs. The cocoon covering is first spun upon some surface, the eggs enclosed, the ball prepared, and the last act is attach- ing it to the spinnerets. Of
. 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 SENSES AND TITEIR ORGANS. 297 time when, having deposited the eggs within the little circular patch, she rolls the cover around thein into a ball, and then attaches the ball to her spinnerets. This is undoubtedly the universal method with spiders that carry about their egg sacs. The cocoon covering is first spun upon some surface, the eggs enclosed, the ball prepared, and the last act is attach- ing it to the spinnerets. Of course, during this process, a spider whose eyesight is so good that it can perceive its prey at a distance of several inches, must of necessity have seen its cocoon. It would be impossible for us to reach any other conclusion. The confusion in maternal recognition and selection of her offspring cannot, therefore, be accounted for by defective sight. Among the Theridioid spiders is a large group of species which Black- wall has placed under the genus Walckenaera, which present some re- Bye markable peculiarities in the location of the eyes. These are Turrets, ^listributed on the anterior part of the cephalothorax, which sometimes in females and usually in males is remarkably ele- vated. The drawings here presented (Figs. 289-293) are taken from Black- wall's descriptions of Walckenaiira acumina- ta,' and represent one of the most remarkable of those turret like de- velopments of the ca- put for the reception of eyes.''^ The length of the female (Fig. 292) is about one-seventh of an inch. The sexes are similar in color, but the male (Fig. 289) is smaller than the fe- male, and the anterior prominence of its ceph- alothorax is much more elongated and slender, measuring about one- twentieth of an inch in length. This eye tur- ret is elevated vertical- ly and dilated near the middle and at the apex (see Figs. 290, 291), the latter dilatation being separated by a transverse groove
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectspiders, bookyear1889
