But the launch was not even yet a success. A spear of grass growing from the water became entangled in the silken cables, and stopped the fairy craft. The spider rushed at the obstruction, seized it in his mandibles, and, to the astonishment of the watchers, walked down it into the water. Soon he re-appeared and again scrambled aboard. But as he now seemed to be greatly agitated and disturbed, the boys here interfered, and cast off the raft for him, whereupon the skipper settled down as if completely satisfied. If they touched him with a blade of grass, he darted into the water and clung to the under side, coming out when the danger was over. Soon an unfortunate fly alighted near the raft, when the pirate, instead of rowing his boat alongside, actually dashed into the water to secure his victim, swimming back to the raft to devour it at his leisure. The last the boys saw of the spider, he had jumped again at something that rippled the water; but he never returned. Possibly a self-satisfied young frog that soon hopped upon the bank could have explained the absence of the skipper of the now deserted craft. Thoroughly interested, the boys repeatedly watched the spiders, and studied their manners and their labors. They found also another spider, which, although it did not make a raft, had no fear of the water, and frequently went fishing; while Dick’s father told them of still another that lived under water by carrying down bubbles of air with it. Its home, too, might be called a queer diving-bell, as may be seen from the illustration. [Illustration: THE SPIDER THAT LIVES UNDER WATER.] There are certain ants that show quite as much intelligence as the spider, and the “driver ants” not only build boats, but launch them, too; only, these boats are formed of their own bodies. They are called “drivers,” because of their ferocity. Nothing can stand before the attacks of these little creatures. Large pythons have been killed by them in a single night, while chickens, lizards, and other animals in Western Africa flee from them in terror. To protect themselves from the heat they erect arches under which numerous armies of them pass in safety. Sometimes the arch is made of grass and earth gummed together by some secretion, and again it is formed by the bodies of the larger ants, which hold themselves together by their strong nippers, while the workers pass under them. [Illustration: THE DRIVER ANTS FORMED INTO A FLOATING BALL.]