y a dozen Dytisci, or water beetles, whose diving
performances are so curious to watch. One day, meaning no harm and for
want of a better receptacle, I fling among them a couple of handfuls
of caddis worms. Blunderer that I am, what have I done! The corsairs,
hiding in the rugged corners of the rock work, at once perceive the
windfall. They rise to the surface with great strokes of their oars;
they hasten and fling themselves upon the crowd of carpenters. Each
pirate grabs a sheath by the middle and strives to rip it open by
tearing off shells and sticks. While this ferocious enucleation
continues with the object of reaching the dainty morsel contained
within, the caddis worm, close pressed, appears at the mouth of the
sheath, slips out and quickly decamps under the eyes of the Dytiscus,
who appears to notice nothing.

I have said before that the trade of killing can dispense with
intelligence. The brutal ripper of sheaths does not see the little white
sausage that slips between his legs, passes under his fangs and madly
flees. He continues to tear away the outer case and to tug at the silken
lining. When the breach is made, he is quite crestfallen at not finding
what he expected.

Poor fool! Your victim went out under your nose and you never saw it.
The worm has sunk to the bottom and taken refuge in the mysteries of the
rock work. If things were happening in the large expanse of a pond, it
is clear that, with their system of expeditious removals, most of the
lodgers would escape scot-free. Fleeing to a distance and recovering
from the sharp alarm, they would build themselves a new scabbard and all
would be over until the next attack, which would be baffled afresh by
the selfsame trick.

In my narrow trough, things take a more tragic turn. When the sheaths
are done for, when the caddis worms that are too slow in making off have
been eaten up, the Water beetles return to the rockery at the bottom.
Here, sooner or later, there are lamentable happenings. The naked
fugitives are discovered and, succulent morsels that they are, are
forthwith torn to pieces and devoured. Within twenty-four hours, not
one of my band of caddis worms is left alive. In order to continue my
studies, I had to lodge the water beetles elsewhere.

Under natural conditions, the caddis worm has its persecutors, the most
formidable of whom appears to be the Water beetle. When we consider
that, to thwart the brigand's attacks, it has invented the ide