Many of the most brilliant butterflies are so colored because they are unpalatable, even uneatable, flaunting their warnings in the face of the lizard, which might eat them unawares were they not so conspicuous. They can flutter lazily about, with no attempt at concealment, preserved by their own poison. In making the injurious butterfly resplendent, nature saves both the butterfly and the bird which might have gulped it down. Others are preserved by having adopted bark-designs or leaf-color or twig-shapes. Some even float about mimicking each other, if advantageous to do so. Some gain protection by imitating the brilliantly colored but uneatable butterflies for which they are mistaken. Mimicry or warning, each protects as is most beneficial, by concealing or making conspicuous. Seen and recognized, they are not molested; or, hidden, they escape notice. How varied are their habits! Poisonous ones fly slowly. Others merely frisk about, toying with life, air, and sunlight; skirt-dancers they are called (_megaluras_), “sown and carried away again by the light air.” Some heavy-bodied butterflies gain protection by flight so rapid as to make them mistaken for humming-birds. The broad, strong strokes of the wide-winged _morphos_ float them across wide rivers. The flight of butterflies is a biologist’s problem, as well as their colored juices and seasonal forms. Some, flying low, have their greatest brilliancy on the under side of the wings; others, flying high, are dull underneath to protect them from enemies below, as the bell-bird, whose home is in the dazzling sunshine above the tree-tops, is made invisible to any eyes looking upward by its snow-white plumage and transparent wings. “Crepuscular” butterflies emerge at sunset. Such are the _caligos_, amazing creatures equipped on the under side with an owl’s head, which can terrify their pursuers by merely turning wrong side out. All animals are suspicious of a strange-looking eye; and at dusk, when the butterfly descends to the jungle pool to drink, the owl-eyes are particularly effective. The harmless butterfly spreads the one view of itself to the enemy which could save its life, and continues slowly to sip the dark water.