Bewilderedly, they looked around them.

Ahead of them, barely to be seen for the trunks of giant trees intervening, was a smoothly-rounded mountain. Majestic and aloof it soared, dwarfing all near it—the termitary which, yesterday, had been but waist-high. There was their eventual goal; but meanwhile their immediate surroundings roused their greater interest—and all their alertness!

When Dennis had said they would find a common grass plot a wild and exotic jungle, he had spoken perhaps more truly than he knew. At any rate, the jungle they now found themselves in was something to exceed man's wildest dreams.

Far over their heads towered a wilderness of trees. But such trees! Without branches, shooting up and over in graceful, tangling curves, their trunks oddly flat and ribbonlike and yellow-green. It was impossible to look on them as grass stems.

Here and there the trees had fallen, presenting a tangled wilderness of leathery, five-foot-wide strips. Webs of roots, tough and gnarled, whitish in color, curled in all directions to catch the feet and baffle the eye. It was an appalling underbrush. And it was an underbrush, moreover, in which there was plenty of wild life!

A hairy, pulpy thing, reddish in color, with gauzy wings and a myriad flashing eyes scuttled close to them as though drawn by curiosity to inspect them. As big as an eagle it appeared to them; both grasped their spears; but soon, with a wild whistle of its wings, it rose up through the tangle of underbrush and hummed off. A fruit fly.

And now a monstrous thing appeared far off, to stalk like a balloon on twenty-foot legs in their direction. With incredible quickness it loomed over them. Six feet through, its body was roughly spherical, and carried on those amazingly long, jointed legs. It stared at them with beady, cruel eyes, but finally teetered on its way again, leaving them untouched.

"I'll never again be able to see a daddy longlegs without shivering," said Jim. His voice was unconsciously sunk to little more than a whisper. This was a world of titanic dangers and fierce alarms. Instinct cautioned both of them to make no more noise than necessary. "We had better make for your termitary at once."

Dennis had been thinking that for some time. But he had been unable to locate a termite tunnel anywhere. Matt had been supposed to set them down near one. No doubt, to his own mind, he had placed them near one of the termite highways. But his ideas of distance were now so radically different from theirs that Dennis, at least, was unable to see a tunnel opening anywhere.

He spoke his thoughts to Jim. "There must be a tunnel opening somewhere very near us," he concluded. "But I—Good heavens!"

Both crouched in wary alarm, spears held for a thrust, if necessary, at the frightful thing approaching them from the near jungle.

Thirty feet long, it was, and six feet through, a blunt-ended, untapered serpent that glistened a moist crimson color in the rays of the sun. The trees quaked and rocked as it brushed against them in its deliberate advance. Dead leaves many feet across and too heavy for the combined efforts of both men to have budged, were pushed lightly this way and that as the monster moved. The very ground seemed to shake under its appalling weight.

"If that comes after us," breathed Jim, "we're through!"

But now Denny drew a long breath of relief.

"Be still," he said. "Make no sound, and no move, and it will probably pass us by. It's blind, and couldn't harm us in any way—unless it rolled on us."

The two stood motionless while the nightmare serpent crashed by. Then, with the earthworm fading into the distance, they resumed their hunt for the near tunnel entrance.

Jim, whose eyes were more accustomed to searching jungle depths, finally saw it—a black hole leading down into a small hill about two hundred yards ahead of them. He pointed.

"There we are. Come on."

Laboriously they set out toward it. Laboriously because at every step some almost insuperable hurdle barred their way. A fallen grass stalk was a problem; sometimes they had to curve back on their tracks for sixty or eighty feet in order to get around it. A dead leaf, drifted there from the trees near at hand, was almost a calamity, necessitating more circuitous maneuvering.

With every yard the realization of the stark peril that was now theirs increased.

A grasshopper, blundering to the ground within a rod of them, nearly crushed them with its several tons of weight. A bumblebee, as big as a flying elephant and twice as deadly, roared around them for several minutes as though debating whether or not to attack them, and finally roared off leaving them shaken and pale. But the most startling and narrow of their narrow escapes occurred an instant after that.

They had paused for an instant, alert but undecided, to stare at a coldly glaring spider that was barring their path. It was a small spider, barely more than waist-high. But something in its malevolent eyes made the two men hesitate about attacking it. At the same time it was squatting in the only clear path in sight, with tangles of stalks and leaves on either side. A journey around the ferocious brute might be a complicated, long-drawn-out affair.

Their problem was decided for them.

Overhead, suddenly roared out a sound such as might have been made by a tri-motored Fokker. There was a flash of yellow. The roar increased to an ear-shattering scream. Something swooped so breathlessly and at the same time so ponderously that the men were knocked flat by the hurricane of disturbed air.

A fleeting struggle ensued between some vast yellow body and the unfortunate spider. Then the spider, suddenly as immobile as a lump of stone, was drawn up into the heavens by the roaring yellow thing, and disappeared. A wasp had struck, and had obtained another meal.

"Thank God that thing had a one-track mind, and was concentrating on the spider," said Jim, with a rather humorless laugh.

Dennis was silent. He was beginning to realize that he knew too much about insects for his peace of mind. To Jim, insects had always heretofore been something to brush away or step on, as the circumstance might indicate. He had no idea, for example, of exactly what fate it was he had just missed. But Denny knew all about it.

He knew that if the wasp had chosen either of them, the chosen one would have felt a stabbing thing like a red-hot sword penetrate to his vitals. He knew that swift paralysis would have followed the thrust. He knew that then the victim would have been taken back, helpless and motionless as the spider was, to be laid side by side with other helpless but still conscious victims in the fetid depths of the wasp's nest. And he knew that finally an egg would have been laid on the victim's chest; an egg that would eventually hatch and deliver a bit of life that would calmly and leisurely devour the paralyzed food supply alive.

"Let's hurry," he suggested, glancing up to see if any more wasps were hovering about.

The lowering tunnel mouth was very near now. Barely twenty yards away. What with the crowding monsters around them, the tunnel began to look like a haven. Almost at a run, they continued toward it.

Then a commotion like that which might be made by a mighty army sounded in the underbrush behind them. Dennis looked back over his shoulder.

"Hurry!" he gasped, suddenly accelerating his pace into frank flight. "Ants...."

Jim glanced back, too—and joined Denny in his flight. Pouring toward them at express train speed, flinging aside fallen stalks, climbing over obstructions as though no obstructions were there, was coming a grim and armored horde. Far in the lead, probably the one that had seen the men first and started the deadly chase, was a single ant.

The solitary leader was a monster of its kind. As tall as Jim, clashing in its horny armor, it rushed toward the fugitives.

"It's going to reach the tunnel before we do," Jim panted. "We've got to kill the thing—and do it before the rest get to us...."

The monster was on them. Blindly, ferociously it hurled its bulk at the things that smelled like termites however little they resembled them. The termite-paste was, in this instance, the most deadly of challenges.

Jim stepped to the fore, with his spear point slanted to receive the onslaught, spear butt grounded at his feet.

Whether the six-legged horror would have had wit enough to comprehend the nature of the defense offered, and would have striven to circumvent it, had time been given it, is a question that will never be answered. For the thing wasn't given the time.

In mid-air it seemed to writhe and try to change the direction of its leap. But it was on the point and had transfixed itself before its intelligence, however keen, could have functioned.

The fight, though, was by no means over. With five feet of steel piercing it through, it whirled with hardly abated vitality toward Dennis. Its gargoyle head came close and closer.

Dennis sprang sideways along its length, lifted the pointed bar he held, and dashed it down on what looked to him a vital spot—the unbelievably slender trunk that held its spatulate abdomen to its armored chest.

There was a crack as the bar smashed down on the weak point. The monster sank quivering to the ground. An instant later it was up, but now its movements were dazed and sluggish as it dragged its half-paralyzed abdomen after it, and fumbled and caught on the heavy bar that transfixed it.

Jim caught the bar and tugged it. "My spear!" he cried. "Denny—help!"

Together the two wrenched to jerk the spear loose from the horny armor of the dying ant. The rest of the pack were very near now.

"We'll have to let it go...." panted Denny.

But at that instant their desperate efforts tore it loose from the convulsively jerking hulk. They darted into the tunnel mouth with the racing horde scarcely twenty yards behind them.

Without hesitation the ants poured in after them. Jim and Dennis leaped forward, in pitch darkness, now and then bumping heavily against a wall as the tunnel turned, but having at least no trouble with their footing: the floor was as smooth as though man-made.

Behind them they could hear the armored horde crashing along in the blackness. The smashing noise of their progress was growing louder. The two had run perhaps fifty yards in the darkness. Another fifty, and they would be caught!

But now, just as their eyes—sharpened also by the danger they were in—began to grow accustomed to the gloom, they saw ahead of them a thing that might have stepped straight out of a horrible dream.

Six feet of vulnerable, unarmored body, amply protected by horny head and shoulders and ten feet of awful, scissor-mandibles, faced them. The creature was doing a strange sort of war dance, swaying its terrible bulk back and forth rhythmically, while its feet remained immovable. An instant it did this, then it charged at the two men. Simultaneously the crashing of the fierce horde behind sounded with appalling nearness—the noise and odor of the ants preventing the huge termite guard in front of the men from recognizing and approving the smell of the termite-paste that covered their bodies.

"Follow me!" snapped Denny, remembering that the hideous attacking thing before them was blind, and gaining from that knowledge swift inspiration.

Jim gathered his muscles to follow at command. But he almost shouted aloud as he saw Denny leap—straight toward the enormous, snapping mandibles.

In an instant, however, Denny's idea was made clear. With a slide that would have done credit to any baseball player, the entomologist catapulted on his chest past the snapping peril. Jim followed, with not a foot to spare. They were not past the soft rear-parts of the thing, but they were at least past its horrible jaws. And before the monster could turn its unwieldy bulk in the tunnel, the ants were upon it.

For a few seconds, blinded to their own danger by the fascination of the struggle going on before them, the two men witnessed the grim watcher of the tunnel as it drove back wave after wave of attacking ants.

Two at a time, the invaders charged that wall of living horn. And two at a time they were swept against the walls, or slashed in two by the enormous mandibles. One against an army; but it was a full minute or so before the one began to weaken.

"Come," whispered Dennis, at last. "If what I think is going to happen occurs, this will be no place for us."

They went ahead, with the din of battle dying behind them, till they saw a small tunnel branching off beside the main stem. Into this they squeezed. But as Jim started to go farther down its constricted length, Dennis stopped him.

"We're fairly safe here, I think. We'll stay and watch...."

Silently, motionless, they lurked in the entrance of the side-avenue, and peered out at the main avenue they had just left. And now that avenue began to buzz with traffic.

First, more of the horrors with the enormous scissor-mandibles began to stream past them. In twos and threes, then in whole squads, they lumbered by, bound for the ant army that had invaded their sanctum.

Not quite too far ahead to be out of sight, the defenders halted. Several of their number went forward to help the dying Horatius. The rest lined up in a triple row across a wide patch in the tunnel, presenting a phalanx it would appear that nothing could beat.

"How do they know enough to gather here from distant parts of this hollow mountain?" whispered Jim to Denny. "How do they know their city is besieged just at this spot, and that their help is needed?"

Dennis shrugged. His eyes were shining. This was the kind of thing he had come here for. This unhampered observation of a strange and terrible race at war and at work—it was well worth all the personal risks he might run.

"No man can answer your question, Jim. They're blind—they can't see their danger so as to know how to combat it. They couldn't hear, and be alarmed by, the vibrations of battle for a distance of more than a few yards. My only guess is that they are constantly and silently commanded by the unknown intelligence, the ruling brain, that hides deep in the earth beneath us and directs these 'soldier' termites in some marvelous way—though itself never seeing or hearing the actual dangers it guards against."

"The queen?" suggested Jim.

Again Denny shrugged. "Who knows? She might be the brains, as well as the egg layer, of the tribe. But don't talk too much. The vibration of our voices might lead them to us in spite of their blindness."

Now the main avenue before them was humming with a new kind of traffic. From side to side it was being filled with a new sort of termite. These were smaller than the soldiers, and entirely unprotected by either horn armor plate or slashing mandibles.

Each of these carried an unwieldy block of gleaming substance. And each in turn dropped its block in a growing wall behind the savage defenders against the ants, and fastened it in place with a thick and viscous brown liquid that dried almost immediately into a kind of cement.

"The workers," whispered Dennis, enthralled. "The building blocks are half-digested wood. The cement is a sort of stuff that exudes from their own bodies. In ten minutes there will be a wall across the tunnel that no ants on earth could penetrate!"

"But the home guards, the brave lads and all that sort of thing, will be shut off on the outside of the wall with the enemy. And there are hundreds of the enemy," protested Jim.

"A necessary sacrifice," said Denny. "And so perfect is their organization that no one, including the soldiers to be sacrificed, ever makes any objection."

Jim shivered a little. "It's terrible, somehow. It's—it's inhuman!"

"Naturally. It's insectian, if there is such a word. And a wise man once predicted that the termite organization, being so much more perfect a one than man's, indicated the kind of society man would at some time build up for himself. In ten or twelve more centuries we, too, might go off in millions and deliberately starve to death because the ruling power decided there were too many people on earth. We, too, might devour our dead because it was essential not to let anything go to waste. We, too, might control our births so that we produced astronomers with telescopes in their heads instead of regular eyes, carpenters with hammer and saw instead of hands, soldiers with poison gas sacs in their chests so they could breathe death and destruction at will. It would be the perfect state of society."

"Maybe—but I'm glad I'll be dead before that times comes," said Jim with another shiver.

By now the wall ahead of them was complete. On the other side of it the soldier termites stolidly fought on to their certain death. On the near side, the workers retreated to unknown depths in the great hollow mountain behind them. The main avenue was once more clear, and, save for a few workers hastening on unknown errands, deserted.

"That act's over," sighed Dennis. "But it may well be no more than a curtain raiser to the acts to come. Shall we be on our way? We're hardly on the fringe of the termitary yet—and I want to get at the heart of it, and into the depths far beneath it. Depths of hell, we'll probably find them, Jim. But a marvelous hell, and one no man has ever before seen."

They left their little haven and moved along the main tunnel toward the heart of the termitary, walking easily upright in this tunnel which was only one of many hundreds in the vast, hollowed mountain—which loomed into the outer sunshine to almost a height of a yard.