together by the builder's legs and more or less arranged by the
undulating movement of the hinder part. This gives a kind of
incoherent and ill defined suspended belt, a narrow hammock with a
number of loose catches; for the various bits of which it is made
up are respected by the teeth and extended from place to place
beyond the main cords of the roots. Here, without much trouble, is
the support, suitably fixed by natural moorings. A few threads of
silk, casually distributed, make the frail combination a trifle
more secure.

And now to the work of building. Supported by the suspended belt,
the caddis worm stretches itself and thrusts out its middle legs,
which, being longer than the others, are the grapnels intended to
seize things at a distance. It meets a bit of root, fastens on to
it, climbs above the point gripped, as though it were measuring the
piece to a requisite length, and then, with the fine scissors of
its mandibles, cuts the string.

There is at once a brief recoil, which brings the animal back to
the level of the hammock. The bit detached lies across the worm's
chest, held in its forelegs, which turn it, twist it, wave it
about, lay it down, lift it up, as though trying for the best
position. Those forelegs make admirably dexterous arms. Being
less long than the other two pairs, they are brought into immediate
contact with those primordial implements, the mandibles and the
spinneret. Their delicate terminal jointing, with a movable and
crooked finger, is the caddis worm's equivalent of our hand. They
are the working legs. The second pair, which are exceptionally
long, serve to spear distant materials and to give the worker a
firm footing when measuring a piece and cutting it with the pliers.