Il6 NATURE STUDY 



lines, this is called the "outer free zone;" between the spiral zone 

 and the center of the snare there is another zone free from spiral 

 or circular lines, or with these lines very far apart, this is called 

 the "inner free zone*'; the central part or central zone of the snare 

 has a close spiral in it, and in this central zone the spider if it has 

 no side retreat usually rests. Touch one of the radii or one of the 

 foundation lines with a pencil point; touch the spiral with a pen- 

 cil; a difference in the character of the two kinds of lines is at once 

 manifest. The spiral thread is "sticky," the radii and founda- 

 tion lines are not sticky. The web is made of two kinds of silk. 

 If a bit of the spiral line be examined under a magnifier it will 

 be seen that ranged along the silken thread, like beads on a 

 string, are many tiny globules or drops. These drops are a sticky, 

 viscous sort of silk, which does not dry and harden as the usual 

 spider silk does. These sticky drops make the spiral line much 

 more effective as a snare. Throw an insect into the web and 

 observe the behavior of web and spider. 



If possible, observe the spinning of an orb-web. Tear partly 

 away an already made web, and if the spider is not too badly 

 frightened, she will probably rebuild the web. Parts of this 

 work of rebuilding, at least, can probably be observed. The 

 spider works in a regular way, putting in first the foundation and 

 radial lines, and then the spiral lines. Two sets of spiral lines 

 are put in; a first set, which is put in from the center outwards, 

 is not viscid, and serves as a scaffolding upon which the spider 

 works when putting in the -second set. The second set is viscid 

 and is put in from the outer part of the web toward the center. 

 The temporary spiral or scaffolding is torn out as the work of 

 putting in the viscid permanent spiral progresses. The work ot 

 building the web includes a great deal of interesting behavior on 

 the part of the spider, the delicate manipulation of the viscid 

 lines, and the almost geometrically accurate disposition of the 

 lines composing the snare, combining to render the whole per- 

 formance little sort of marvelous. 



