er, at the moment of the
exodus, a sudden instinct arises, to disappear, as promptly and for ever,
a few hours later. This is the climbing-instinct, which is unknown to
the adult and soon forgotten by the emancipated youngling, doomed to
wander homeless, for many a long day, upon the ground. Neither of them
dreams of climbing to the top of a grass-stalk. The full-grown Spider
hunts trapper-fashion, ambushed in her tower; the young one hunts afoot
through the scrubby grass. In both cases there is no web and therefore
no need for lofty contact-points. They are not allowed to quit the
ground and climb the heights.

Yet here we have the young Lycosa, wishing to leave the maternal abode
and to travel far afield by the easiest and swiftest methods, suddenly
becoming an enthusiastic climber. Impetuously she scales the wire
trellis of the cage where she was born; hurriedly she clambers to the top
of the tall mast which I have prepared for her. In the same way, she
would make for the summit of the bushes in her waste-land.

We catch a glimpse of her object. From on high, finding a wide space
beneath her, she sends a thread floating. It is caught by the wind and
carries her hanging to it. We have our aeroplanes; she too possesses her
flying-machine. Once the journey is accomplished, naught remains of this
ingenious business. The climbing-instinct conies suddenly, at the hour
of need, and no less suddenly vanishes.

CHAPTER VII: THE SPIDERS' EXODUS

Seeds, when ripened in the fruit, are disseminated, that is to say,
scattered on the surface of the ground, to sprout in spots as yet
unoccupied and fill the expanses that realize favourable conditions.

Amid the wayside rubbish grows one of the gourd family, _Ecbalium
elaterium_, commonly called the squirting cucumber, whose fruit--a rough
and extremely bitter little cucumber--is the size of a date. When ripe,
the fleshy core resolves into a liquid in which float the seeds.
Compressed by the elastic rind of the fruit, this liquid bears upon the
base of the footstalk, which is gradually forced out, yields like a
stopper, breaks off and leaves an orifice through which a stream of seeds
and fluid pulp is suddenly ejected. If, with a novice hand, under a
scorching sun, you shake the plant laden with yellow fruit, you are bound
to be somewhat startled when you hear a noise among the leaves and
receive the cucumber's grapeshot in your face.

The fruit of the gard