Deep in the jungle, they at last came to a little open stretch where the Professor had often collected before and which to-day seemed full of butterflies. Never had Will imagined such a riot of color and beauty as there dazzled his eyes. Some of the butterflies were red and yellow, the colors of Spain. Others were green, purple, and blue, bordered and spangled with spots of silver and gold. Then there were the strange transparent "glass-wings." One of these, the _Hetaira esmeralda_, Will was convinced must be the most beautiful of all flying creatures. Its wings were like clear glass, with a spot of mingled violet and rose in the center of each one. At a distance, only this shimmering spot could be seen rising and falling through the air, like the wind-borne petals of some beautiful flower. Indeed, as the procession of color drifted by, it seemed to the boy as if all the loveliest flowers on earth had taken to themselves wings, or that the rainbow-bridge of the sky had been shattered into fragments which were drifting slowly down to earth.
The largest of them all were the swallowtails, belonging to the same family as the tiger, and blue and black swallowtail, which Will had so often caught in Cornwall. One of that family gleamed in the sunlight like a blue meteor as it flapped its great wings, seven inches from tip to tip and of a dazzling blue, high above the tree-tops. Another member of the same family, and nearly as large, was satiny white in color. Professor Ditson told Will that both of these varieties were almost unknown in any collection, as they never came within twenty feet of the ground, so that the only specimens secured were those of disabled or imperfect butterflies which had dropped to the lower levels.
"Why couldn't I climb to the top of one of those trees with a net and catch some?" inquired Will, looking wistfully up at the gleaming shapes flitting through the air so far above him.
"Fire-ants and wasps," returned the professor, concisely. "They are found in virtually every tree. No one can stand the pain of an ant's bite, and one sting of a Maribundi wasp has been known to kill a strong man."
That night, tired out by their long day of hunting, the whole party went to bed early. Will's sleeping-room was an upper screened alcove, just large enough to hold a single hammock. Somehow, even after his long hard day, he did not feel sleepy. Great trees shadowed his corner, so thick that even the stars could not shine through their leaves, and it seemed to Will as if he could stretch out his hands and lift up dripping masses of blackness, smothering, terrifying in its denseness. From a far-away tree-top the witch-owl muttered over and over again that mysterious word of evil, "Murucututu, murucututu," in a forgotten Indian tongue. He had laughed when Pinto told him a few nights before that the owl was trying to lay a spell on those who listened, but to-night in the dark he did not laugh.