_ CO ee a a ee a ns ee 
“ 7 of he: 
100 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 
a motion which causes the threads to rapidly contract and gather into a 
little ball of loops near the surface of the web. (Fig. 92.) The spider then 
swings her abdomen well to one side of this flossy hump of loops, as at 
Fig. 93, drawing after her a ray of milky filaments. Next, she draws back 
her abdomen, which is held close to the shield space, pulls the taut lines 
; over the flossy mass (Fig. 94), and the spinnerets are then 
moved back and forth with a lateral motion like the 
spreading of mortar by a mason’s trowel, thus pushing, 
beating, or spreading the loops against the cross lines of 
the hub. The spider repeats these motions, at the same 
time shifting her position occasionally, thus revolving her- 
self by her feet around the circle of the shield. As the 
spinnerets, of course, revolve with the body, the weaving 
process is continually repeated, and the shield gradually ve 
Fic, 93. A third position. formed. The movement of the spinnerets is from the 
The abdomen thrown : 
to one side, drawing centre of the hub outward, and it follows that as the 
a ae nee ray Of oreatest quantity and thickness of silk issue at the first 
expulsion and gradually diminish, the centre receives 
the heaviest coating, and this decreases toward the margin. The fact that 
the shield is more closely woven in the centre is thus accounted for. 
This describes the ordinary method by which Argiope’s shield is spun, 
but there are other modes. One continually finds, in studying the new made 
webs of this species, that the zigzag ribbon entirely traverses the hub, in 
which there is no trace of the shield except a few straggling lines. In this 
case the ribbon has evidently been spun first. Again, one sees the same 
extended ribbon, and, in addition, on either side are woven one or more 
zigzag bands, arranged in ares of circles, which occupy the 
space usually taken by the shield. In the course of time 
these would be overspun, so that the hub would be occu- 
pied by the thick shield which is common to the species. 
When the hub is covered over, the spider proceeds to 
insert her zigzag ribbon. She moves downward to a point 
a little below the shield. Dropping her spinner- 
ets to one of the radii, she attaches all the num- 
erous filaments at once, say at the point 1, Fig. 
95. She then raises her abdomen and begins to ascend, ge ota fae 
moving slowly, and dragging after her a band of silk. to the looped masses, 
A . which the spinnerets are 
As she mounts, she swings her spinnerets across to the Oppo- heating and squeezing 
site radius, drops them at the point 2, and attaches her dow» 
ribboned dragline thereto. Of course, the upward movement of the spider 
and the simultaneous lateral motion of her spinnerets give to the ribbon a 
diagonal course, so that the second point of attachment, 2, will be higher 
than the first point, 1. So also when the abdomen is swung back again, the 
spider meanwhile still climbing, the third point, 3, will be higher than the 
Insertion 
of Zigzag. 
