A Dyak village about thirty miles above Sarawak was their destination; the crew of the boat was composed of half a dozen natives with strong arms, and as they had promise of a liberal payment on condition of making a rapid journey, they applied all their strength to the oars. Luckily, they were favored by the tide, and by a breeze blowing up stream, and very soon after getting under way they spread the sail of coarse matting and laid their oars at one side. The Dyaks along the coast are excellent sailors, but their boats are not built after the most approved models of naval architecture; under the best circumstances, they rarely make more than six miles an hour, and the most of them are satisfied with three or four. It took about seven hours of rowing and sailing for our friends to reach the village; but the time passed pleasantly, as there was an abundance of things of interest on the shore, and each bend of the stream revealed something new. The forest was dense, and contained several varieties of trees they had not yet seen, and there was an apparent abundance of animal and insect life. Every few minutes the boys would catch sight of a bright-winged bird or a gaudy butterfly, and they managed to secure several specimens of the latter. While they were halted for a few moments under a tree that overhung the water, Fred's attention was attracted by a butterfly that fluttered among the leaves for a moment, and then seemed to disappear like the harlequin in a play. While he was looking for it there came another and then another, and each of them in turn vanished like the first. Frank was as much excited as Fred over the strange phenomenon, and asked the Doctor what could have become of the butterflies, as he was certain they had not flown away, and he could not see them among the leaves. "Look closely at the leaves," said the Doctor, "and perhaps you will find them." "I've looked at every leaf," Fred answered; "but there is no butterfly to be seen." "I've found one," said Frank, as he took what appeared to be a leaf between his thumb and forefinger. [Illustration: LEAF BUTTERFLY IN FLIGHT AND REPOSE.]