un shows his face again."

He paused, however, to transfix upon his spear-head one of their
wounded but still fluttering foes, that he might be able to show the
tribe what manner of monsters they had had to deal with. Both A-ya and
Mo followed his example; and they all ran off down the glade searching
for Loob, whom they soon found and bearing their strange trophies on
their spear-heads they went on. The monsters, clinging sullenly to
their perches, rolled baleful eyes of emerald and rose and amethyst
upon them as they went, but lifted never a wing to follow them. Ten
minutes later the sun came out again. Then the monsters all sprang
hurtling into the air, and darted hither and thither above the glade
in shoals of iridescent radiance, seeking their prey. But Grom and
A-ya, Mo and Loob triumphant in spite of their wounds, were by this
time far away among the inland thickets, where those intolerable eyes
could not search them out, nor the clashing wings pursue.

CHAPTER X

THE TERRORS OF THE DARK

I

From the topmost summit of that range of pointed hills which held the
caves and the cave-mouth fires of his people, Grom stared northward
with keen curiosity. To east and south and west he had explored, ever
seeking to enlarge the knowledge and strengthen the security of his
tribe. But to northward of the pointed hills lay league on league of
profound jungle--grotesque and enormous growths knitted together
impenetrably by a tangle of gigantic, flame-flowered lianas. And in
those rank, green glooms, as Grom had reason to believe, there lurked
such monsters as even he, with all his resources of fire and novel
weapons, had so far shrunk from challenging.

But beyond the expanse of jungle stretched another line of hills,
their summits not saw-toothed like his own, but low and gently
rounded, and of a smoky purple against the pure turquoise sky. These
hills Grom was thirsting to explore. They might contain caves more
roomy than those of his own hills--spacious and suitable to give
shelter to his tribe, which was now finding itself somewhat cramped.
Moreover, it had always seemed to Grom that there might be a mystery
behind those hills, and to his restless imagination a mystery was
always like a stinging goad.

In all this neighborhood the crust of earth was thin as plainly
appeared from the fringe of wavering volcanic flames which, during all
the five years since the coming of the tribe, had been dancing from
the