Page:Popular Science Monthly Volume 37.djvu/549

 the bottom of his cage. Evidently he was puzzled; heretofore, when he climbed those walls, he had invariably found a rest at top—tin at one end and cardboard at the other; but this vast expanse of light was a marvel to be* pondered and not too rashly accepted. That mantis never did fly; he crawled around the edge of the cage at last to a spot where it touched a higher shelf of the flower-stand, and, as if he had just discovered that he was a prisoner no longer, scrambled with more haste than discretion up to the next shelf, where a huge black spider, whose lair was just under the verge of the shelf, pounced upon him so suddenly that retreat was impossible. The mantis was taken completely by surprise, and the start he gave was so violent that but for the spider's swift, encompassing arms, he must have fallen backward off the shelf. Thereupon ensued a terrific struggle; the devil's-riding-horse made a brave resistance, but the spider would have proved too much for him, so his late jailer, armed with a broom-straw, separated the combatants. The spider retired to the shadow of the shelf, and the mantis, climbing upon the leaves of a mespilus-tree that reached against the farther side of the flower-stand, disappeared from our ken forever.



OLOR, as such, is not necessarily of any value to an organism. Organic substances frequently possess a chemical and physical structure which causes certain light-waves to be absorbed; or, the elements of tissues may be so arranged that light is scattered, or interference colors are produced. Thus blood is red, fat is white, and the external surface of the air-bladder in certain fishes has a metallic luster, like silver. In such cases there is no reason why we should inquire as to the use or meaning of the color in the animal economy; the color, as such, has no more meaning than it has in a crystal of sulphate of copper or iron. Such colors are the incidental results of chemical or physical structure, which is valuable to the organism on its own account. This argument will be still further enforced if we remember that the colors in question are, strictly speaking, not colors at all. Blood and fat are so constituted that they will be red and white, respectively, in the presence of light, but they can not be said to possess these colors in their normal position, buried beneath the opaque surface of an animal.