on went to the door
and looked out.

The electric wall had temporarily been dropped, and Kin Ibo and the
main body of the pirates were hastily entering the camp with their
improvised power-sledges that bore heavy loads of machinery and
materials.

Kenniston heard Kin Ibo reporting shrilly to John Dark, "We lost two
men to the Vestans on the way here--and nearly lost two more! All this
activity has drawn them from all over the asteroid! Look at that!"

Outside the electric wall, which had been hastily re-raised, could be
glimpsed the shapes of lurking asteroidal animals. Meteor-rats, big
striped cats, flame-birds--and every one of those lurking animals bore
attached to its neck one of the little gray Vestan parasites.

John Dark was saying harshly, "We've got to have the rest of those
materials to repair the _Falcon_."

"I tell you, it'd be suicide to try another trip through those
jungles!" expostulated the Martian. "Those Vestans are devils!"

"Bah, you Martians are all alike--no good when your superstitions get
aroused," snorted Dark contemptuously. "I'll take the men down myself.
Come on, men--unload those sledges and we'll go back to the wreck."

His indomitable personality drove the scared, unwilling pirates into
the task. Again the electric wall was faded out for a moment to let
them out.

When they returned some time toward morning, Kenniston heard the crash
of atom-guns heralding their approach. And when the wall was
momentarily dropped, John Dark and his men stumbled into the camp with
their loaded sledges in sweating haste.

"Turn on the wall again--quick!" bellowed Dark's bull voice. "The
jungle's swarming with the gray devils now--they got five of us on the
way back!"

Ricky, looking over Kenniston's shoulder, spoke appalledly. "Good God,
Lance--look at them! I didn't know there _were_ so many Vestans!"

Outside the barrier of shimmering electricity, scores of animals and
birds dominated by the dreaded little gray parasitical creatures were
now swarming. And their number seemed growing every minute.

"All this activity of the night has drawn the Vestans from far and
wide," Kenniston muttered. "I don't like it. If that electric wall
should fail, the creatures would be in on us in a moment."

Dark himself seemed to feel something of the same apprehension, for
he was shouting urgent orders. "Hook up those atomic welders, and
start putting the new plates into the _Falcon's_ tail. Kin Ibo, have
y