matter wherein the caddis worm deserves our attention.
With a perseverance which repeated trials do not tire, it makes itself
a new tube when I strip it. This is opposed to the habits of the
generality of insects, which do not recommence the thing once done, but
simply continue it according to the usual rules, taking no account
of the ruined or vanished portions. The caddis worm is a striking
exception: it starts again. Whence does it derive this capacity?

I begin by learning that, given a sudden alarm, it readily leaves its
scabbard. When I go fishing for caddis worms, I put them in tin boxes,
containing no other moisture than that wherewith my catches are soaked.
I heap them up loosely, to avoid any grievous tumult and to fill the
space at my disposal as best I may. I take no further precaution. This
is enough to keep the caddis worms in good condition during the two or
three hours which I devote to fishing and to walking home.

On my return, I find that a number of them have left their houses. They
are swarming naked among the empty scabbards and those still occupied
by their inhabitants. It is a pitiful sight to see these evicted ones
dragging their bare abdomens and their frail respiratory threads over
the bristling sticks. There is no great harm done, however; and I empty
the whole lot into the glass pond.

Not one resumes possession of an unoccupied sheath. Perhaps it would
take them too long to find one of the exact size. They think it better
to abandon the old clouts and to manufacture cases new from top to
bottom. The process is a rapid one. By the next day, with the materials
wherein the glass trough abounds--bundles of twigs and tufts of
watercress--all the denuded worms have made themselves at least a
temporary home in the form of a tube of rootlets.

The lack of water, combined with the excitement of the crowding in the
boxes, has upset my captives greatly; and, scenting a grave peril,
they have made off hurriedly, doffing the cumbersome jacket, which is
difficult to carry. They have stripped themselves so as to flee with
greater ease. The alarm cannot have been due to me: there are not many
simpletons like myself who are interested in the affairs of the pond;
and the caddis worm has not been cautioned against their tricks. The
sudden desertion of the crib has certainly some other reason than man's
molestations.

I catch a glimpse of this reason, the real one. The glass pond was
originally occupied b