In all parts of the world frogs are usually protectively colored with browns or greens; and little tree-frogs are either curiously mottled to imitate dead leaves or bark, or they are green like the leaves they rest upon. These protectively colored frogs are always eagerly sought after by snakes and other enemies. But there are some frogs that are very conspicuously colored and that hop about with impunity, being avoided by the snakes and birds of prey. Such is a little frog in Nicaragua which with its “scarlet vest and stockings of blue” is very conspicuous in its native haunts.[9] Such, also, is a small toad found in South America, which is colored a bright vermilion and an intense black, which crawls about in the sunshine over the sands of arid places. Both of these animals are altogether avoided by the frog-eating creatures, because they have disagreeable properties that make them inedible. In tropical America the very poisonous snake Elaps (Plate VI) is found abundantly. Its style of coloration is very conspicuous and one that does not occur in any other group of snakes, consisting alternately of rings of red, black, and yellow, or red and black of varying width and arranged in different patterns. Snake-eating birds and mammals have learned, through hereditary experiences, to avoid these snakes with gay livery because they are poisonous and therefore dangerous. In Plate VII the conspicuously-colored black and yellow salamander is an animal with warning coloration. It is inedible and avoided by carnivorous birds. These warning colorations have been evolved through the Natural Selection of fortuitous useful color variations in the ancestors during the Geologic Ages. [Illustration: PLATE VI.—Illustrating Warning Coloration (_Elaps_) and especially Mimicry (_Erythrolamprus_). Elaps is a very poisonous reptile and Erythrolamprus is harmless. Reproduced (and modified) from Romanes’s “Darwin and after Darwin.” By courtesy of the Open Court Publishing Company.] =Mimicry.= Protective resemblance of a harmless animal to another of a different species that is harmful is known as mimicry. Mimicry is bound up with and altogether dependent upon warning coloration. Some beetles are protected by having integuments, etc., of very great hardness. Several genera of weevils are in this way saved from attack by insect-loving birds. These weevils are often closely imitated in appearance by softer and more eatable species of different genera from the weevils. Wasps and bees are often mimicked by insects of other orders. Insectivorous birds are very active in hunting out the edible beetles (Longicornia), and everywhere in tropical regions these beetles so closely resemble other insects which are avoided by the birds that the longicorns are very frequently avoided and thus protected.