ARGIOPE AND HER RIBBONED ORB. : 99 
used. However, in one snare noted, built within a lodge across the angle 
of two walls, the zigzag was prolonged into a series of lines like the rounds 
of a ladder, spun across the corner quite down to the floor. This was used 
as a gangway, by which on one occasion, at least, the occupant descended 
to the floor and thence escaped from the room. 
The entire system of spinningwork thus described, shield and ribbons, is 
often five inches in length, and extends across the Free space, dividing it 
into two nearly equal parts. The spider hangs at the centre upon 
rie the shield which thus covers the lower part of her body. Her 
legs are well extended, but the corresponding pairs, the two fore 
legs and the two hind legs, are approximated so that these members are 
arranged somewhat X-shaped. The feet, however, are usually turned out- 
ward, the points of contact of the legs being at the tibia. 
‘The main purpose of the shield I believe to be protective. It certainly 
may serve as a strong screen against attack of enemies from the under or 
ventral side of the animal. Asa rule 
that side of the shield which looks 
outward fromthe site is occupied by 
her; but at times the animal hangs 
also upon the opposite face, next the 
leaves or shrubbery. I haye often 
seen an alarmed spider scurry through 
the open space from the outer to the 
inner face of the shield. Again, the 
. _ spiders which on one day were found 7 Sy eerie 
wing the sheeted ton, Hanging to the inside of the shield, of lines gathered into 
aca tiles igre would be seen clinging to the outside 1°? 
ningwork drawn out. on the next day; and, again, some on one side and some 
Ce eee on the other. TI have fully satisfied myself by experiment 
that a threatened danger will be avoided by placing the shield between her- 
self and the apprehended peril. This is done by a dextrous movement, part 
swinging, part crawling, through the free zone. 
The central shield and zigzag lines are not of slow growth, but are made 
immediately after the spinning of the web. The manner of spinning is as 
follows: When the orb is finished in the ordinary way, as heretofore de- 
scribed, the spider goes to the hub, cuts out the temporary central anchor- 
ages which she puts into her mouth, and proceeds to weave in the 
Manner of shield. She holds-on with her fect to the lines of the notched zone, 
arias throws the abdomen upward and backward as far as convenient, 
the spinnerets being flared or extended to their utmost width 
instead of being closed upon each other. The threads, which issue from 
all the spinning tubes in streams of delicate filaments, are, of course, attached 
to the shield and drawn out by this motion and the action of the hind legs. 
(Fig. 91.) The abdomen is then dropped down against the shield space, 
