The little tribe of human beings passed precariously behind a group of a hundred excited insect warriors, and before the following group of forty equally excited black insects. Burl hurried on with his following, putting many miles of perilous territory behind before nightfall. Many times during the day they saw the sudden billowing of a red-brown dust-cloud from the earth, and more than once they came upon the empty skin and drooping stalk of one of the red mushrooms, and more often still they came upon the mushrooms themselves, grown fat and taut, prepared to send their deadly spores into the air when the pressure from within became more than the leathery skin could stand. That night the tribe hid among the bases of giant puff-balls, which at a touch shot out a puff of white powder resembling smoke. The powder was precisely the same in nature as that cast out by the red mushrooms, but its effects were marvelously--and mercifully--different; it was innocuous. Burl slept soundly this night, having been two days and a night without rest, but the remainder of his tribe, and even Saya, were fearful and afraid, listening ceaselessly all through the dark hours for the menacing sounds of creatures coming to prey upon them. And so for a week the march kept on. Burl would not allow his tribe to stop to forage for food. The red mushrooms were all about. Once one of the little children was caught in a whirling eddy of red dust, and its mother rushed into the deadly stuff to seize it and bring it out. Then the tribe had to hide for three days while the two of them recovered from the debilitating poison. Once, too, they found a half-acre patch of the giant cabbages--there were six of them full grown, and a dozen or more smaller ones--and Burl took two men and speared two of the huge, twelve-foot slugs that fed upon the leaves. When the tribe passed on it was gorged on the fat meat of the slugs, and there was much soft fur, so that all the tribefolk wore loin-cloths of the yellow stuff. There were perils, too, in the journey. On the fourth day of the tribe's traveling, Burl froze suddenly into stillness. One of the hairy tarantulas--a trap-door spider with a black belly--had fallen upon a scarabæus beetle, and was devouring it only a hundred yards ahead. The tribefolk, trembling, went back for half a mile or more in panic-stricken silence, and refused to advance until he had led them a detour of two or three miles to one side of the dangerous spot. Long, fear-ridden marches through perilous countries unknown to them, through the golden aisles of yellow mushroom forests, over the flaking surfaces of plains covered with many-colored "rusts" and molds; pauses beside turbid pools whose waters were concealed by thick layers of green slime, and other evil-smelling ponds which foamed and bubbled slowly, which were covered with pasty yeasts that rose in strange forms of discolored foam.