ned the throttle.

The beetle's name was Dworn, and he was twenty-one years old. The flesh
and blood of him, that is. The rest, the steel-armored shell, the wheels
and engine and hydraulic power-system, the electric sensory
equipment--all of which was to his mind as much part of his identity as
his own skin, muscles, eyes and ears--was only five years old.

Dworn's face, under his sleep-tousled thatch of blond hair, was boyish.
But there were hard lines of decision there, which the last months had
left.... Tonight by the reckoning of his people, he was still a youth;
but when tomorrow dawned, the testing of his wanderyear would be behind
him, and he would be adult, a warrior of the beetle horde.

Sand spilled from the beetle's dull-black carapace as it surged from its
hiding-place. It drifted, its motor only a murmur, along the shoulder of
the dune. Dworn eyed his offending fuel gauge darkly; he would very much
have liked to be on his way at top speed, toward the year's-end
rendezvous of the horde under the shadow of the Barrier.

He began cruising slowly, at random, across the rolling moonlit waste of
wind-built dunes, watching for spoor.

He spied, and swerved automatically to avoid, the cunningly concealed
pit of a sand devil, strategically placed in a hollow of the ground.
Cautiously Dworn circled back for a second look. The conical pit was
partly fallen in, unrepaired; the devil was obviously gone.

The burrowing machine would, Dworn knew, have had fuel and other
supplies somewhere in its deep lair, buried beneath the drifted sand
where it spent its life breathing through a tube to the surface and
waiting for unwary passers-by to skid into its trap. But Dworn
regretfully concluded that it would not be worth while digging on the
chance that whatever had done away with the devil had not rifled its
stores.... He swung the beetle's nose about and accelerated again.

On the next rise, he paused to inspect the track of a pill-bug; but to
his practiced eye it was quickly evident that the trail was too old,
blowing sand had already blurred the mark of heels, and the bug probably
was many miles away by now.

A mile farther on, luck smiled on him at last. He crossed the fresh and
well-marked trail of a caterpillar--deeply indented tread-marks,
meandering across the dunes.

* * * * *

He began following the spoor, still slowly, so as not to lose it or to
run upon its maker unawares. A