There are many instances of protective imitation or mimicry in nature, but none are more pronounced, more perfect or more interesting than that shown by the leaf butterflies. Briefly defined, the phenomenon of mimicry is that relation which obtains when “a certain species of plants or animal possesses some special means of defense from its enemies and some other species inhabiting the same district or a part of it, and not itself provided with the same special means of defense, closely resembles the first species in all external points of form and color, though often very different in structure and unrelated in the biological order.” Many animals, such as some tree-lizards, resemble the colors of the environment in which they live, either for protection from enemies or in order that they may more easily catch their prey. Some arboreal snakes hang from the boughs of trees like the drooping ends of creeping vines. The coloring of the under surface of the wings of the leaf butterflies very closely resembles the color of a dried leaf. As dried leaves vary in color and appearance, so do the butterflies vary in the color and markings of their wings. It is said that even in the same species, the under surface of the wings may be of various shades of brown, yellow, ash and red. But the imitation of the dried leaf does not alone rest on the color, for often, here and there, may be seen small groups of dark colored spots which strikingly resemble the patches of fungi that are so common on leaves. The mimicry of this butterfly is purely protective and not for the purpose of deceiving its prey. Dr. Alfred Russel Wallace in his “Malay Archipelago” writes of this butterfly as he found it in its native element. He says, “This species was not uncommon in dry woods and thickets, and I often endeavored to capture it without success, for after flying a short distance it would enter a bush among dry or dead leaves, and however carefully I crept up to the spot, I could never discover it till it would suddenly start out again, and then disappear in a similar place. At length I was fortunate enough to see the exact spot where the butterfly settled, and though I lost sight of it for some time, I at length discovered that it was close before my eyes, but that in its position of repose it so closely resembled a dead leaf attached to a twig as almost certain to deceive the eye, even when gazing full upon it. I captured several specimens on the wing, and was able fully to understand the way in which this wonderful resemblance is produced.