Suddenly there was a loud sound, like a big drum, in the water directly under the boat. "Tom, tom! Tom, tom!" It startled Chie Lo, and she exclaimed: "What is it, Chin? What is it?" "It must be a drum-fish, Chie Lo. Nothing else could make a sound like that." "Of course, Chin. It was all so quiet, and then the sound was so sudden, I didn't think for a moment what it could be." They had often seen this ugly-looking fish, which is never eaten by the people of their country. It is able to make a loud noise by means of a sort of bladder under its throat, and it is well called the "drum-fish." The children still went onward, keeping time with their sculls. Suddenly the air around them blazed with countless lights, and a moment afterward the darkness seemed blacker than ever. Then, again the lights appeared, only to be lost as suddenly, while Chin and his sister held their oars and watched. "Aren't they lovely?" said Chie Lo. "I never get tired of looking at the fireflies." It is no wonder she thought so. The fireflies of Siam are not only very large and brilliant, but they are found in great numbers. And, strange to say, they seem fond of gathering together on certain kinds of trees only. There they send forth their light and again withdraw it at exactly the same moment. It seems as though they must be under the orders of some leader. How else do they keep together? "I can hear the trumpeter beetle calling along the shore," said Chin, as the boat floated about. "He makes a big noise for his size, and takes his part in the song of the night. There must be hundreds of lizards singing up there among the bushes, too, and I don't know what else." "I suppose the parrots are asleep in the tree-tops by this time, as well as the monkeys. Don't you love to go about in the woods, Chin?" "It is almost the best fun in the world, I think. Oh, Chie Lo, I saw something the other day I didn't tell you about. You made me think of it when you spoke of the monkeys. Father and I had gone a long way up the river in the canoe to get wild bananas. We had just turned to come home when I saw a crocodile ahead of us, lying close to the shore. His wicked mouth was wide open and his eyes were glittering. "All at once I saw what was the matter. A chain of monkeys was hanging from a tree-top above him. They were having sport with the monster. The lowest monkey would suddenly strike out with his paw and touch the crocodile's head when he was off his guard. Then the whole chain of monkeys would swing away as quick as a flash, and the crocodile would snap too late. "Oh, he did get so angry after awhile, it made me laugh, Chie Lo. The monkeys grew bolder after awhile, and chattered more and more loudly.