urgent
business, and then, when her round is finished, to return to her hut. In
fact, it is the road which I see her follow, in going and coming. But is
that all? No; for, if the Epeira had no aim in view but a means of rapid
transit between her tent and the net, the foot-bridge would be fastened
to the upper edge of the web. The journey would be shorter and the slope
less steep.

Why, moreover, does this line always start in the centre of the sticky
network and nowhere else? Because that is the point where the spokes
meet and, therefore, the common centre of vibration. Anything that moves
upon the web sets it shaking. All then that is needed is a thread
issuing from this central point to convey to a distance the news of a
prey struggling in some part or other of the net. The slanting cord,
extending outside the plane of the web, is more than a foot-bridge: it
is, above all, a signalling-apparatus, a telegraph-wire.

Let us try experiment. I place a Locust on the network. Caught in the
sticky toils, he plunges about. Forthwith, the Spider issues impetuously
from her hut, comes down the foot-bridge, makes a rush for the Locust,
wraps him up and operates on him according to rule. Soon after, she
hoists him, fastened by a line to her spinneret, and drags him to her
hiding-place, where a long banquet will be held. So far, nothing new:
things happen as usual.

I leave the Spider to mind her own affairs for some days, before I
interfere with her. I again propose to give her a Locust; but, this
time, I first cut the signalling-thread with a touch of the scissors,
without shaking any part of the edifice. The game is then laid on the
web. Complete success: the entangled insect struggles, sets the net
quivering; the Spider, on her side, does not stir, as though heedless of
events.

The idea might occur to one that, in this business, the Epeira stays
motionless in her cabin since she is prevented from hurrying down,
because the foot-bridge is broken. Let us undeceive ourselves: for one
road open to her there are a hundred, all ready to bring her to the place
where her presence is now required. The network is fastened to the
branches by a host of lines, all of them very easy to cross. Well, the
Epeira embarks upon none of them, but remains moveless and self-absorbed.

Why? Because her telegraph, being out of order, no longer tells her of
the shaking of the web. The captured prey is too far off for her to