On the other hand, we have a little faggot of bits of
wood, very dry, equal in length and each possessing the thickness of
a good sized pin. The two sorts of building material lie side by side,
mingling their threads and sticks. The animal can make its choice from
the lump.

A few hours later, having recovered from the shock of losing its sheath,
the caddis worm sets to work to manufacture a new one. It settles across
a bunch of tangled rootlets, which are brought 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. Lastly, the hind legs, of medium length, afford a
support when the others are busy.

The caddis worm, I was saying, with the piece which it has removed
held crosswise to its chest, retreats a little way along its suspended
hammock until the spinneret is