le of Throgs in action, and to be an eye-witness to such
action, were two vastly different things. He shivered in spite of the
warmth of the Survey Corps uniform.

As yet he had sighted none of the aliens, only their plate-shaped
flyers. They would stay aloft until their long-range weapon cleared out
all opposition. But how had they been able to make such a complete
annihilation of the Terran force? The last report had placed the nearest
Throg nest at least two systems away from Warlock. And a patrol lane had
been drawn about the Circe system the minute that Survey had marked its
second planet ready for colonization. Somehow the beetles had slipped
through that supposedly tight cordon and would now consolidate their
gains with their usual speed at rooting. First an energy attack to
finish the small Terran force; then they would simply take over.

A month later, or maybe two months, and they could not have done it. The
grids would have been up, and any Throg ship venturing into Warlock's
amber-tinted sky would abruptly cease to be. In the race for survival as
a galactic power, Terra had that one small edge over the swarms of the
enemy. They need only stake out their new-found world and get the grids
assembled on its surface; then that planet would be locked to the
beetles. The critical period was between the first discovery of a
suitable colony world and the erection of grid control. Planets in the
past had been lost during that time lag, just as Warlock was lost now.

Throgs and Terrans ... For more than a century now, planet time, they
had been fighting their queer, twisted war among the stars. Terrans
hunted worlds for colonization, the old hunger for land of their own
driving men from the over-populated worlds, out of Sol's system to the
far stars. And those worlds barren of intelligent native life, open to
settlers, were none too many and widely scattered. Perhaps half a dozen
were found in a quarter century, and of that six maybe only one was
suitable for human life without any costly and lengthy adaption of man
or world. Warlock was one of the lucky finds which came so seldom.

Throgs were predators, living on the loot they garnered. As yet, mankind
had not been able to discover whether they did indeed swarm from any
home world. Perhaps they lived eternally on board their plate ships with
no permanent base, forced into a wandering life by the destruction of
the planet on which they had originally been spawned. B