umerous. They fly by day as well as by night, and attack
everything that moves. They've taken several of our Family, and I think
they've made heavy depredations on the peoples that inhabit this region.
We spiders would have abandoned the location before now, but we feared
to be caught migrating in the open...."

* * * * *

Dworn gazed apprehensively out at the glaring desert that was rolling
past the spider windows. The news that the aerial killers also operated
by day was most unwelcome. But as yet there was no sign of an enemy.

He said, "The little ground machines--unarmored, made of aluminum.
They're allied in some way to the flying ones, aren't they?"

"We think so. Wherever the flying machines have made a kill, the
crawlers appear before long to carry away the spoils. And if they're
attacked--the fliers come swooping down within minutes to defend or
avenge them. So most of the other inhabitants have learned to leave the
crawlers alone; it's extremely dangerous to meddle with them."

Dworn could confirm that fact from his own observation.

Evidently the spider folk, even though they came from beyond the Barrier
as the mysterious others apparently had too, knew little more than he
himself had already discovered. But--there was one more question.

"Do you know," he asked tensely, "where these strangers' home base is?
Where do they fly from?"

The girl looked doubtful. "We're sure only that it's somewhere beyond
the Rim, where we used to live."

That much, too, he had guessed. Dworn subsided into glum silence, as
Qanya impassively guided the machine on its way, covering distance at a
surprising speed.

Then, even by the unaccustomed daylight, Dworn recognized first one
landmark and then another, and knew they were approaching the spot where
he had been trapped last night. A weird return, riding as master in the
monstrous machine that had snared him!

As the great tilted rock hove in view, Dworn strained for the first
glimpse of his abandoned vehicle. When he saw it, lying still overturned
in the shadow of the boulder, he sighed in relief. Its door was ajar,
where Qanya must have dragged him stunned from the machine last night
... but it appeared unscathed. The fear at the back of his mind, that
scavengers might have happened on it--in which case they would have had
it dismantled and carried away by now--was happily unrealized. For that
he perhaps had partly to thank the enemy