54 



A^IICIUCAN SPIDEKS AND THEIR SPINNINGWORK. 



1. Ill Full Urb smires the spiral (_H)necii- 

 trifs cross all the radii, appearing to form 

 (complete circles. (See Fig. 47.) They are 

 divided into Simple and Compound snares. 

 a. A Simple orb web is simply an orb of 

 radiating straight lines cros.sed by spiral or 

 looped lines. The snare of the Furrow spi- 

 der (Epeira strix) is a typical example. 



Ij. A Compound orbweb adds to the sim- 

 ple orV) a system of netted or retitelarian lines 

 crossed and joined at differt'ut angles, and 

 placed above and on either sick' of the upper 

 Fig. 49. Subdivisions of an orbweb. part of the orlj, or placed bclow the orl). The 

 snare of the Labyrinth Spider (Epeira labyrinthea) is an example. Sim- 

 ple orbicular snares may be approximately arranged into three groups 

 according as they have the Hub Meshed, Sheeted, or Open. 



I am not aware that any arrangement, description, or nomenclature of 

 the various parts of the orbweb has ever been attempted apart from the 

 following, which will therefore be found convenient and perhaps 

 th^'o b^ ■sufficiently comprehensive. ^ The orb may be naturally divided 

 into the Central Space, CS, the Spiral Space, SS, and the Foun- 

 dation Space, FS. (See Fig. 49.) 



The Central Space is included between the centre of the orl) and the 

 origin of the Spiral Sj^ace. It has three 

 distinct parts, the Hub, the Notched zone, 

 and the Free zone. The Hub is a small 

 circular part immediately surrounding the 

 centime, which is either wholly open, or 

 covered in whole or in i)art by sjjinning- 

 work. 



1. The Meshed Hub is wholly or partly 

 covered by a series of iiTegularly shaped 

 meshes, through which one can often trace 

 the continuation of the radii as zigzag lines. 

 In fact, it niay be considered as a small 

 rudimentary and irregular orbweb (Fig. 

 50). Usually it nearly corresponds in size 

 to the length (including the legs) of the 

 spider that has woven it. 



The spider when waiting for her prey 

 upon her snare is frequently and at night 



generally stretched upon or near this hub, fig. so. Meshed hub and central space. 



' Kiiyt puhlishecl in "Our Continent," Philailclpliia, No. 33, piifrc 3(52, 18S2, an.l -Pro- 

 ceedings of the Acadcniy of Natural Sciences," Philadelphia, 1882, page 257. 



