. The Cambridge natural history. Zoology. ORB-WEBS 347 to which the spider can put in the viscid spiral, which it com- mences at the circumference. Its action now becomes exceedingly careful and deliberate, though liy no means slow, and so great is its absorption in the work that it may be observed quite closely with a hand-lens without fear of interrupting it. The proceeding consists in drawing out from its spinnerets with one (or both) of its hind legs successive lengths of a highly elastic line, which it stretches just at the moment of fixing it to a radius, and then lets go with a snap. Th
. The Cambridge natural history. Zoology. ORB-WEBS 347 to which the spider can put in the viscid spiral, which it com- mences at the circumference. Its action now becomes exceedingly careful and deliberate, though liy no means slow, and so great is its absorption in the work that it may be observed quite closely with a hand-lens without fear of interrupting it. The proceeding consists in drawing out from its spinnerets with one (or both) of its hind legs successive lengths of a highly elastic line, which it stretches just at the moment of fixing it to a radius, and then lets go with a snap. There is no hesitation or pause for consideration, but there is a peculiar deliberateness in drawing out each length of the thread which, together \v'ith stretching and sudden re- lease, require explanation. Now, it has already been mentioned that the framework and radii of the snare are not at all moist or adhesive. This, however, is not the case with the spiral, upon which the spider chiefly relies in capturing its prey. A close examination of it—even with the naked eye—will show it to be beaded over with little viscid globules which, under a low magnifying power, are seen to be arranged with remarkable regularity. A very convenient method of investigation is to carry off a newly-constructed web—or, better still, one not quite finished— on a piece of plate glass, to which it will adhere by reason of the viscid spiral, and on which it may be examined at Fig. 190.—A, B, C, D, Stage-s in the formation of the viscid globules of the web. Immersion in a staining fluid will colour the viscid spiral, and show its structure in a striking manner. It will appear to con- sist of a thread strung with beads of two sizes, occurring with pretty uniform alternation, though two of the larger beads are often separated by two or more of the smaller. Until recently it was supposed that the deposition of these beads upon the spiral line was a subsequent operation, and, in view. P
Size: 3281px × 762px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1895
