t he had no choice.

He worked for an hour and it was no good. Even with the rifle as a
pry, he could not budge the tree.

He lay back, defeated, breathing hard, wringing wet with perspiration.

He grimaced at the sky.

All right, Cytha, he thought, you won out in the end. But it took a
_skun_ to do it. With all your tricks, you couldn't do the job
until....

Then he remembered.

He sat up hurriedly.

"Cytha!" he called.

The Cytha had fallen into a hole that had opened in the ground. The
hole was less than an arm's length away from him, with a little debris
around its edges still trickling into it.

Duncan stretched out his body, lying flat upon the ground, and looked
into the hole. There, at the bottom of it, was the Cytha.

It was the first time he'd gotten a good look at the Cytha and it was
a crazily put-together thing. It seemed to have nothing functional
about it and it looked more like a heap of something, just thrown on
the ground, than it did an animal.

The hole, he saw, was more than an ordinary hole. It was a pit and
very cleverly constructed. The mouth was about four feet in diameter
and it widened to roughly twice that at the bottom. It was, in
general, bottle-shaped, with an incurving shoulder at the top so that
anything that fell in could not climb out. Anything falling into that
pit was in to stay.

This, Duncan knew, was what had lain beneath that too-smooth interval
between the two sets of Cytha tracks. The Cytha had worked all night
to dig it, then had carried away the dirt dug out of the pit and had
built a flimsy camouflage cover over it. Then it had gone back and
made the trail that was so loud and clear, so easy to make out and
follow. And having done all that, having labored hard and stealthily,
the Cytha had settled down to watch, to make sure the following human
had fallen in the pit.

* * * * *

"Hi, pal," said Duncan. "How are you making out?"

The Cytha did not answer.

"Classy pit," said Duncan. "Do you always den up in luxury like this?"

[Illustration]

But the Cytha didn't answer.

[Illustration]

Something queer was happening to the Cytha. It was coming all apart.

Duncan watched with fascinated horror as the Cytha broke down into a
thousand lumps of motion that scurried in the pit and tried to
scramble up its sides, only to fall back in tiny showers of sand.

Amid the scurrying lumps, one thing remained intact, a fragile ob