148 
Orbweavers. 
AMERICAN SPIDERS AND THEIR SPINNINGWORK,. 
Each concentric of the scaffolding, which is marked by the 
arrows in the figure (Fig. 138), makes a marked division between the in- 
Fic. 189. Snare of Nephila, woven on a wire 
hoop. (After Wilder.) 
termediary spirals, which are thus divided 
into groups or bands, adding much to the 
peculiar form of the snare. 
Wilder states! that the free sector or 
space uncovered by beaded spirals in the 
snare of Nephila, in natural site is equal 
on an average to about one-sixth the sur- 
face of the orb. He, however, gives a 
drawing of a web made by a spider in 
captivity upon a circular wire frame, which 
has a free sector equal to two-thirds of the 
orb.2 (Fig. 189.) No doubt this abnormal 
form was due to the artificial conditions 
under which the spider plied her industry. 
Prof. Wilder is sufficiently explicit in his 
description to allow us to present the diagramatic or restored web, Fig. 
140, as approaching the characteristic form in natural site.* 
It thus closely 
een SS eer 
approximates that of Epeira triara- 
nea and Zilla. The spirals do not 
form complete circles, but are looped 
across the radii, in a manner already 
described, and in spinning them the 
spider does not move around the 
web, but returns upon her course 
from one side to a corresponding 
point on the other. The web thus 
made is strong enough to support 
a light straw hat when hung up- 
on it. 
Gosse speaks of the immense 
snares of Nephila as one of the 
obstructions to free travel 
eae in the woods of Jamaica. 
oe ig ACO Ts * ar 1 
nasa: These, he says, are in- 
fested with the great long 
bodied spider with brush tufted 
/ 
LTS 
Vi 
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Zz 
Ay i 
LS 
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ag 
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Via. 140. A diagramatic snare of Nephila, composed from 
the descriptions and sketches of Prof. Wilder. 
1 Proceedings American Association, 1873, page 265. 
2This has led Emerton, Structure and Habits of Spiders, page 66, to the erroneous state- 
ment that her snare “consists of loops running round about quarter of a circle.” 
* Prof. Wilder, in his paper, Proceedings American Association, 1873, page 272; also 
Galaxy, page 111, 1869, and on the Triangle Spider, Popular Science Monthly, page 653, 
1875, gives an outline cut of Plumefoot’s orb, which corresponds with that of Fig. 140. 
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