beating of the night.

And then, he could run no longer, and he clutched a tree to keep from
falling, his arms trembling about it, and his face pressed against the
impersonal roughness of the bark. There was no wind, but the tree swayed
back and forth and his body with it.

Then, as abruptly as light goes on when a switch is thrown, the noise
vanished. Utter silence, and at last he was strong enough to let go his
grip on the tree and stand erect again, to look about to get his
bearings.

One tree was like another, and for a moment he thought he'd have to stay
here until daylight. Then he remembered that the sound of the surf would
give him his directions. He listened hard and heard it, faint and far
away.

And another sound--one that he had never heard before--faint, also, but
seeming to come from his right and quite near.

He looked that way, and there was a patch of opening in the trees above.
The grass was waving strangely in that area of moonlight. It moved,
although there was no breeze to move it. And there was an almost sudden
_edge_, beyond which the blades thinned out quickly to barrenness.

And the sound--it was like the sound of the surf, but it was continuous.
It was more like the rustle of dry leaves, but there were no dry leaves
to rustle.

Mr. Smith took a step toward the sound and looked down. More grass bent,
and fell, and vanished, even as he looked. Beyond the moving edge of
devastation was a brown floor of the moving bodies of _kifs_.

Row after row, orderly rank after orderly rank, marching resistlessly
onward. Billions of _kifs_, an army of _kifs_, eating their way across
the night.

Fascinated, he stared down at them. There was no danger, for their
progress was slow. He retreated a step to keep beyond their front rank.
The sound, then, was the sound of chewing.

He could see one edge of the column, and it was a neat, orderly edge.
And there was discipline, for the ones on the outside were larger than
those in the center.

He retreated another step--and then, quite suddenly, his body was afire
in several spreading places. The vanguard. Ahead of the rank that ate
away the grass.

His boots were brown with _kifs_.

Screaming with pain, he whirled about and ran, beating with his hands
at the burning spots on his body. He ran head-on into a tree, bruising
his face horribly, and the night was scarlet with pain and shooting
fire.

But he staggered on, almost blindly, running, writhing,