etle to go.

The next pocket was a long, narrow, horizontal fold, and I hoped to
find real excitement among its aquatic folk; but to my surprise it had
no bottom, but was a deep chute or socket, opening far below to the
sand. However, this was not my discovery, and I saw dimly a weird
little head looking up at me--a gecko lizard, which called this
crevice home and the crabs neighbors. I hailed him as the only other
backboned friend who shared the root-world with me, and then listened
to a high, sweet tone, which came forth in swinging rhythm. It took
some time for my eyes to become accustomed to the semi-darkness, and
then I saw what the gecko saw--a big yellow-bodied fly humming in this
cavern, and swinging in a small orbit as she sang. Now and then she
dashed out past me and hovered in mid-air, when her note sank to a
low, dull hum. Back again, and the sound rose and fell, and gained ten
times in volume from the echo or reverberations. Each time she passed,
the little lizard licked his chops and swallowed--a sort of vicarious
expression of faith or desire; or was he in a Christian Science frame
of mind, saying, "My, how good that fly tasted!" each time the
dipteron passed? The fly was just as inexplicable, braving danger and
darkness time after time, to leave the sunshine and vibrate in the
dusk to the enormously magnified song of its wings.

With eyes that had forgotten the outside light, I leaned close to the
opening and rested my forehead against the lichens of the wall of
wood. The fly was frightened away, the gecko slipped lower, seemingly
without effort, and in a hollowed side of the cavernous root I saw a
mist, a quivering, so tenuous and indistinct that at first it might
have been the dancing of motes. I saw that they were living
creatures--the most delicate of tiny crane-flies--at rest looking like
long-legged mosquitoes. Deep within this root, farther from the light
than even the singing fly had ventured, these tiny beings whirled
madly in mid-air--subterranean dervishes, using up energy for their
own inexplicable ends, of which one very interested naturalist could
make nothing.

Three weeks afterward I happened to pass at high tide in the canoe and
peered into this pocket. The gecko was where geckos go in the space of
three weeks, and the fly also had vanished, either within or without
the gecko. But the crane-flies were still there: to my roughly
appraising eyes the same flies, doing the same dance in e