Tommy Travers and James Dodd, of the Travers Antarctic Expedition, crash in their plane somewhere near the South Pole, and are seized by a swarm of man-sized beetles. They are carried down to Submundia, a world under the earth's crust, where the beetles have developed their civilization to an amazing point, using a wretched race of degenerated humans, whom they breed as cattle, for food. The insect horde is ruled by a human from the outside world--a drug-doped madman. Dodd recognizes this man as Bram, the archaeologist who had been lost years before at the Pole and given up for dead by a world he had hated because it refused to accept his radical scientific theories. His fiendish mind now plans the horrible revenge of leading his unconquerable horde of monster insects forth to ravage the world, destroy the human race and establish a new era--the era of the insect. The world has to be warned of the impending doom. The two, with Haidia, a girl of Submundia, escape, and pass through menacing dangers to within two miles of the exit. There, suddenly, Tommy sees towering over him a creature that turns his blood cold--a gigantic praying mantis. Before he has time to act, the monster springs at them! CHAPTER VII _Through the Inferno_ Fortunately, the monster miscalculated its leap. The huge legs, whirling through the air, came within a few inches of Tommy's head, but passed over him, and the mantis plunged into the stream. Instantly the water was alive with leaping things with faces of such grotesque horror that Tommy sat paralyzed in his rocking shell, unable to avert his eyes. Things no more than a foot or two in length, to judge from the slender, eel-like bodies that leaped into the air, but things with catfish heads and tentacles, and eyes waving on stalks; things with clawlike appendages to their ventral fins, and mouths that widened to fearful size, so that the whole head seemed to disappear above them, disclosing fangs like wolves'. Instantly the water was churned into phosphorescent fire as they precipitated themselves upon the struggling mantis, whose enormous form, extending halfway from shore to shore, was covered with the river monsters, gnawing, rending, tearing. Luckily the struggles of the dying monster carried it downstream instead of up. In a few moments the immediate danger was past. And suddenly Haidia awoke, sat up. "Where are we?" she cried. "Oh, I can see! I can see! Something has burned away from my eyes! I know this place. A wise man of my people once came here, and returned to tell of it. We must go on. Soon we shall be safe on the wide river. But there is another way that leads to here. We must go on! We must go on!" Even as she spoke they heard the distant rasping of the beetle-legs. And before the shells were well in mid-current they saw the beetle horde coming round the bend; in the front of them Bram, reclining on his shell couch, and drawn by the eight trained beetles. * * * * *