58 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 
near the hub where the spider waits, is commonly quite long enough to 
allow the active creature to reach and secure her victim, when capture is 
desirable. When for any reason capture is not desirable or prudence sug- 
gests caution, the nearness of the spider to an insect thus arrested on the 
naked radii brings it within her vision, which at the best seems to be 
limited. On the contrary, insects who strike upon the outer margin are 
not only detained by the viscid beads, but made comparatively harmless. 
5. The Free Zone gives the further advantage of allowing the spider 
easy access to the under part of the 
snare, a convenience which is some- 
times important. It is perhaps worth 
noting here that vertical snares which 
PANS have an open hub appear quite com- 
Wn eee monly to have no free zone, that 
a " part of the web being oceupied by 
the notched zone prolonged to the 
inner boundary of the spirals.!| Thus in either case, although by an inter- 
esting variation in spinning habit, the way is left open for the spider to 
pass from one side of her orb to the other. I have watched with great 
interest the agility of a large Argiope in swinging herself from one side 
of her shield to the other when threatened by danger. I could always by 
demonstrations with finger or pencil cause her to change sides. This was 
done invariably by crawling through the free zone. The space seemed over 
small to give passage to such a large creature, but the elasticity of the 
threads readily permitted the transfer, 
which was made with remarkable deft- 
ness and dexterity. 
The chief purpose of the Notched 
Zone seems to be to strengthen the 
web, and particularly to brace 
and hold in position the radii 
before the spirals are wrought 
in. My observations indicate that the 
notched spirals are invariably woven 
in before the beaded spirals. The outer 
or diverging ends of the radii being supported by the Foundation lines, 
the inner or converging ends by the notched space, the spider begins to 
lay in her foundation spirals from the inner margin of the spiral space, 
working toward the circumference. Thus her operations are conducted 
somewhat after the architectural modes of a human builder erecting a 
ab Mgy 
oS 
Fic. 56. Flossy ribbon braces of Uloborus. 
Notched 
Zone. 
ie 
WING 
Tem 
\ 
Fic. 57. Flossy circular braces of Uloborus. 
of all snares with open hubs. That it is with many I know. The point is one for further in- 
vestigation. 
