These latter are a strange tropical family four hundred strong, and all the very essence of protective coloring. Their habits of life make of them wandering bits of bark, easy to detect when they are in motion, but vanishing utterly when they are quiet. Their similarity in dress is remarkable. They may be large or small, short or long-tailed, with beaks blunt, sharp, straight, curved, thick, or needle-pointed. In these characters they differ; by these points they must know one another. But their colors are almost identical. Their olives or browns invariably warm into rich foxy rufous on wings and tail, while over head and shoulders a shower of light streaks has fallen, bits of sunlight fixed in down. Further details belong to the literature of ornithology. But the colors of the berry-hunters--these baffle description, yet we cannot pass them by in silence. The blood and orange splashed on black of the toucans, the scarlet and yellow of woodpeckers, the soft greens and buffs of flycatchers, all these paled when a flock of manakins or tanagers or honey-creepers came to the tree. Every precious stone found its counterpart in the metallic hues of these exquisite feathered folk. The glory of all was the opal-crowned manakin, a midget in green coat and sulphur waistcoat, with a cap of scaly, iridescent, silvery mother-of-pearl plates, in no way akin to feathers. Until now the life of this Hop o' my Thumb, like those of all his ancestors, had gone smoothly on, with never a human to admire, to wonder, and vainly to echo the question of the great black frog, _Wh--y?_ On the last day of my stay I walked slowly up the trail toward the _canella do matto_. For the last time I strained upward at the well-known branches, and with the very movement there came the voice of the swamp. Its tone was insistent, with a tinge of accusation, a note of censure. _Wh--y?_ and after a little time, _Wh--y?_ I looked about me despairingly. What had I learned after all? Was there any clearing up of the mystery of the jungle? Had my week of scrutiny brought me any closer to the real intimacies of evolution? Or--evading these questions for the time--was there nothing I could do in the few precious moments left? In five minutes I should turn my back on all this wildness, this jungle seething with profound truths, and great solutions within arm's reach. I should pass to the ocean where monotony compels introspection, and finally to the great center of civilization where the veneer covers up all truths. Even if my studies had taught only the lesson of the tremendous insurgence of life, could I not emphasize this, make it a more compelling factor to be considered in future efforts toward the frog's question and mine?