There are other reasons which increase our doubts. The shells hung up are most often empty; but there are also some occupied by the Snail, alive and untouched. What can the Spider do with these snail-shells wherein the animal retreats so far that she cannot reach it? The Spider cannot break the hard shell or get at the hermit through the opening. Then why should she collect these prizes, whose slimy flesh is probably not to her taste? We begin to suspect a simple question of ballast and balance. The House Spider prevents her web, spun in a corner of the wall, from losing its shape at the least breath of air, by loading it with crumbling plaster and allowing tiny fragments of mortar to accumulate. The Clotho Spider dumps down on her abode any more or less heavy object, mainly corpses of insects, because she need not look for these and finds them ready to hand after each meal. They are weights, not trophies; they take the place of materials that must otherwise be collected from a distance and lifted to the top. In this way, a breastwork is obtained that strengthens and steadies the house. Further balance is often given by tiny shells and other objects hanging a long way down. The Clotho knows the laws of balancing; by means of additional weights, she is able to lower the center of gravity and thus to give her dwelling the proper equilibrium and roominess.
Now what does she do in her softly-wadded home? Nothing, that I know of. With a full stomach, her legs luxuriously stretched over the down carpet, she does nothing, thinks of nothing; she listens to the sound of the earth revolving on its axis. It is not sleep, still less is it waking; it is a middle state where the Spider is conscious of nothing except that she is happy. We ourselves, when comfortably in bed, enjoy, just before we fall asleep, a few moments of bliss, when we neither think nor worry; and those moments are among the sweetest in our lives. The Clotho Spider seems to know similar moments and to make the most of them.
CHAPTER XXI
THE SPIDER’S TELEGRAPH-WIRE
Of the six Garden Spiders I have noticed, two only, the Banded and the Silky Spiders, stay constantly in their webs, even under the blinding rays of a fierce sun. The others, as a rule, do not show themselves until nightfall. At some distance from the net they have a rough and ready retreat in the brambles, a hiding-place made of a few leaves held together by stretched threads. It is here that they usually remain in the daytime, motionless and sunk in meditation.
But the shrill light that vexes them is the joy of the fields. At such time, the Locust hops more nimbly than ever, more gayly skims the Dragon-fly. Besides, the sticky web, in spite of the rents suffered during the night, is still in fairly good condition. If some giddy-pated insect allow himself to be caught, will the Spider, at the distance whereto she has retired, be unable to take advantage of the windfall? Never fear. She arrives in a flash. How does she know what has happened? Let us explain the matter.
It is the vibration of the web which tells her, rather than the sight of the captured object. To prove this, I laid upon several Spiders’ webs a dead Locust. I placed the Locust where the Spider might have plainly seen it. Sometimes the Spider was in her web, and sometimes she was outside, in her hiding-place. In both cases, nothing happened at first. The Spider remained motionless, even when the Locust was at a short distance in front of her. She did not seem to see the game at all. Then, with a long straw, I set the dead insect trembling.
That was quite enough. The Banded Spider and the Silky Spider hastened to the central floor, the others, who were in hiding, came down from the branch; all went to the Locust, bound him with tape, treated him, in short, as they would treat a live prey captured under the usual conditions. It took the shaking of the web to decide them to attack.
If we look carefully behind the web of any Spider with a daytime hiding-place, we shall see a thread that starts from the center of the web and reaches the place where the Spider lurks. It is joined to the web at the central point only. Its length is usually about twenty-two inches, but the Angular Spider, settled high up in the trees, has shown me some as long as eight or nine feet.