_THE TRIANGLE. SPIDER: THE ORB SECTOR. 189 
backward, and also clasp the trapline in the approximated claws. But be- 
tween the third and fourth pairs of legs the trapline presents a peculiar 
form. Instead of being drawn taut or held loosely, it has the 
Geog appearance of a coil, and this in fact it is. About three-fourths 
ac ‘ : : : 
Tine of an inch of the trapline, or a portion equal to four times the 
entire length of the spider, is rolled up above the spinnerets and 
the hinder part of the abdomen, between the third and fourth pairs of legs. 
(Fig, 179, cl.) Behind the spider the trapline is in the same taut condi- 
tion that it presents in front of the spider. 
The net is now in perfect condition for operation. The whole front 
part of it, which includes the snare proper, is drawn taut in every cord 
and fibre. (See Fig. 180.) The trapline behind the spider is in 
the same tense condition. The only portion that is relaxed is 
the bit of coil between the last two pairs of legs, and occasion- 
ally (perhaps) the short 
stretch between the front 
legs and the third pair. We 
will now suppose that an 
insect strikes the snare, al- 
though the same effect can 
be produced by touching the 
spider herself or by tickling 
the fibres of her web in a 
manner to imitate the moye- 
ment of a fly. She is not, 
however, easily deceived by 
the latter trick; at least, I 
have rarely been  success- 
ful enough to compel her to spring her net by mimicking the move- 
ments of an insect, and when I desired to make the observation, was 
compelled to touch her gently with a pencil. As soon as the spider per- 
ceives that her prey is trapped, she unclasps simultaneously all the fore 
feet holding upon the trapline, and those of the third pair of legs which 
keep relaxed the coil of slack line. Instantly the entire snare shoots 
forward (Fig. 181), and by a principle of inertia which needs no expla- 
nation, the spiral lines are thrown forward around the insect (Fig. 182), 
whose entanglement is thus secured. With a rapidity so great that the 
eye is not able to follow the details of the movement, the snare is tight- 
ened ; the spider momentarily assumes the previous position of expectancy, 
and again springs her net. This may be repeated several times, Wilder 
having observed six successive springings of the net. 
In this movement the spider appears to shoot forward with her snare, 
but in point of fact she has remained stationary, or at least has advanced 
but a trifle. But now, crawling to the apex of her snare, she seems to 
Springing 
the Snare. 
Fic. 181. A relaxed snare of Hyptiotes, after the snap. 
