It is in the numbers and varieties of insectivorous birds that these forests specially abound. Hundreds of them may be seen at almost any time moving about with the greatest activity, from species no larger than a sparrow to others the size of a crow. There are tanagers, ant-thrushes, fly-catchers and bargets, running up the trees and flitting about the leaves or lower branches. The hustling crowd lose no time, and, although seeming to move in concert, each bird is occupied on its own account in searching bark, leaf or twig. Then again, in a few minutes, all these hosts may disappear and the forest will remain deserted and silent. One bird, the organ bird, is a remarkable songster. When its notes are heard for the first time, it is hard to resist the impression that it is a human voice. It is especially noticeable because of the general absence of song birds in the tropical forests. The numbers and varieties of insects are countless from the gorgeous butterflies to the leaf insects, which it is almost impossible for the uninitiated to discover because of the close resemblance to the foliage which they inhabit. The Amazon is really the despair of the naturalist by reason of the abundance of its plant and animal life. One naturalist reports having found upwards of seven thousand insects in one locality. Included in this list were five hundred and fifty distinct specimens of the butterfly. No description can convey an adequate idea of the beauty and diversity in form of this class of insects. There are many beautifully coloured beetles, whose delicate tints are marvels of beauty. There are flies which swarm along the banks in such numbers as to look like columns of smoke. The ants themselves are an interesting study, for their numbers are legion. There are ants that fly and ants that crawl; some that bite and others that sting; species that are carnivorous and species that are purely vegetable feeders; good and bad, big and little, industrious and lazy. No form of insect life is more interesting than these little creatures that can teach lessons to the human race. The jaguar, or tapir, does not create so great a commotion in the forest, as the armies of foraging ants which oftentimes march. They carry death and destruction to all other forms of insect life which can not fly far enough, or run fast enough, to escape these enemies. Wherever they move the whole animal world is set in commotion, and every living creature is possessed of but one idea, and that to get out of the way just as soon as possible. The ants march along in solid columns in a given direction, clearing the ground, bushes and small trees of every living thing. They will even attack a human being, if he should fail to get out of the way, and a few bites or stings will soon cause him to scamper away as fast as his legs can carry him. [Illustration: A SCENE ON THE AMAZON NEAR ITS MOUTH.]