148 



AMKKK'AN SPIDERS AND THEIR SPINNINGWORK. 



Orbweavers. Jvich concentrie of tliu scaffolding, wliirli is marked l)_y tlie 

 arrows in tlie figure (Fig. I881, irialves a marked division between tbe in- 

 termediary sj)irals, wbich are tbus divided 

 into groups or bands, adding much to the 

 peeuhar form of the snare. 



Wilder states ^ that tlie free sector or 

 space uncovered by beaded spirals in tlie 

 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 

 di-awing of a web made l)y 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 

 ;3 form was due to the artificial conditions 

 Fii,. 139. siuiJL oi ,Nipini;i, Hi.viii ona wire under wliicli the spider plied her industry. 



hoop. (After Wilder.) -nr-i i • 02 • ii T -i. • v ■ 



rrof. Wilder is surhciently explicit in his 



description to allow us to present the diagramatic or restored web, Fig. 



140, as apjiroacliing the characteristic form in natural site.'' Tt thus closely 



approximates that of Ei)eira triara- 



nea and Zilla. The spirals do not 



form complete circles, but are looped 



acro.ss the radii, in a manner already 



described, and in sjiinning 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 tlie 



obstructions to free travel 



maica j^^ ^|^^ woods of Jamaica. 



Nephila : 



Gosse. These, he says, are in- 

 fested with the great long 



.. -Ill £3 l''i''- HO. A diagramatic snare of Nephila, composed from 



bodied spider with brush tutted the descriptions and sketches of Prof. Wilder. 



' Proceedings Amoriciui Association, 1873, page 2G5. 



2 This has led Emerton, Struc-ture and Haljits of Spiders, \>age 6G, to the erroneous state- 

 ment that her snare "consists of loops runniiifr round about ((uarter of a circle." 



' Prof WildiT, in his paper, Proceediufrs .\nieiican .Association, 1S7.'5, page 272 ; also 

 Galaxy, page 111, ISfii), and on the Triangle Spider, Popular Science AInnthly, \nij:e 653, 

 1875, gives an outline cut of Plumefoot's orb, which corresponds with that of Fig. 140. 



