of the House Spider is, as we were saying, a platform for
watching and exploring; it is also a sheet into which the insects caught
in the overhead rigging fall. This surface, a domain subject to
unlimited shocks, is never strong enough, especially as it is exposed to
the additional burden of little bits of plaster loosened from the wall.
The owner is constantly working at it; she adds a new layer nightly.

Every time that she issues from her tubular retreat or returns to it, she
fixes the thread that hangs behind her upon the road covered. As
evidence of this work, we have the direction of the surface-lines, all of
which, whether straight or winding, according to the fancies that guide
the Spider's path, converge upon the entrance of the tube. Each step
taken, beyond a doubt, adds a filament to the web.

We have here the story of the Processionary of the Pine, {30} whose
habits I have related elsewhere. When the caterpillars leave the silk
pouch, to go and browse at night, and also when they enter it again, they
never fail to spin a little on the surface of their nest. Each
expedition adds to the thickness of the wall.

When moving this way or that upon the purse which I have split from top
to bottom with my scissors, the Processionaries upholster the breach even
as they upholster the untouched part, without paying more attention to it
than to the rest of the wall. Caring nothing about the accident, they
behave in the same way as on a non-gutted dwelling. The crevice is
closed, in course of time, not intentionally, but solely by the action of
the usual spinning.

We arrive at the same conclusion on the subject of the House Spider.
Walking about her platform every night, she lays fresh courses without
drawing a distinction between the solid and the hollow. She has not
deliberately put a patch in the torn texture; she has simply gone on with
her ordinary business. If it happen that the hole is eventually closed,
this fortunate result is the outcome not of a special purpose, but of an
unvarying method of work.

Besides, it is evident that, if the Spider really wished to mend her web,
all her endeavours would be concentrated upon the rent. She would devote
to it all the silk at her disposal and obtain in one sitting a piece very
like the rest of the web. Instead of that, what do we find? Almost
nothing: a hardly visible gauze.

The thing is obvious: the Spider did on that rent what she did every
elsewhere