148 



AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



Orbweavers. Each concentric of the scaffolding, whicli is marked by the 



arrows in the figure (Fig. 138) 



Fig. 139. 



Snare of Nephila, woven on a wire 

 hoop. (After Wilder.) 



makes a marked division between tiie in- 

 termediary spirals, wdiich 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. 139.) No doubt this abnormal 

 form was due to the artificial conditions 

 under wdiich 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 



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 

 in the woods of Jamaica. 

 These, he says, are in- 

 fested with the great long 



. n ^ ^^^- ^**'- ^ diagramatic snare of Nephila, composed from 



spider With brush tufted the descriptions and sketches of Prof. Wilder. 



Jamaica 

 Nephila : 

 Gosse. 



bodied 



^Proceedings American Association, 1S7;5, page 2<)5. 



2 This has led Einerton, Structure and Ha])its of Spiders, i)a<j;e fi(), to the erroneous state- 

 ment that her snare "consists of loops running round ahout (juarter of a circle." 



Trof Wilder, in his ])ai)er, Proceedings American Association, 1873, page 27 



>79 ■ 



also 



Galaxy, page 111, 18()i), and on tlic Triangle Spider, I'ii|Milar Science Rloiitldy, page 653, 

 1875, gives an outline cut of PliiiiK'foot's orl), wliicli corresponds with lliat of Kig. 140. 



