The Geometry of the Epeira's Web
But we must not rely too much on this rule, say others. The Angular Epeira, the Pale-tinted Epeira and the Diadem Epeira, or Cross Spider, all three more or less short-limbed, rival the Banded Epeira in the spacing of their lime-snares. The last two even dispose them with greater intervening distances.
We recognize in another respect that the organization of the animal does not imply an immutable type of work. Before beginning the sticky spiral, the Epeiræ first spin an auxiliary intended to strengthen the stays. This spiral, formed of plain, non-glutinous thread, starts from the centre and winds in rapidly-widening circles to the circumference. It is merely a temporary construction, whereof naught but the central part survives when the Spider has set its limy meshes. The second spiral, the essential part of the snare, proceeds, on the contrary, in serried coils from the circumference to the centre and is composed entirely of viscous cross-threads.
Here we have, following one upon the other, by a sudden alteration of the machine, two volutes of an entirely different order as regards direction, the number of whorls and
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