Another high mountain variety has square petals with fringed edges. Found in the jungles of the upper Orinoco is an orchid with blossoms measuring up to 16 inches in diameter. A completely unique orchid has been found growing in water. (All other species live as parasites on trees or rocks—or in the soil like other plants.) Throughout the world there are more than 20,000 species of orchids, the great majority of which are found only in the mountainous regions of the tropics. A few, however, can be found growing as far north as the Arctic Circle. _Nature’s Insecticide: The Millipede_ Far leas malevolent than the centipede—and probably a somewhat more primitive form of animal life—is the millipede or “thousand legs”. It is a strictly vegetarian creature that lives under stones, logs or in rotting tree trunks and feeds on soft roots, leaves and fruits. Millipedes are seldom seen. They shun light, although in the tropics they sometimes come out of their retreats after heavy rains and crawl over the ground. The animal has twenty to forty legs, two pair on each segment of the body—a characteristic in which it differs striking from the centipedes to whom it is only distantly related. Movement is in an almost mathematically straight line, with a series of wave-like undulations in which apparently all the legs on one side of the body move in unison. All millipedes are essentially blind. Their eyes are able only to distinguish light from dark, but as they crawl every inch of their path is explored by their delicately sensitive antennae. So secretive is their life that relatively little is known of their behavior. The female of one European species burrows in the earth, moistens bits of soil with a sticky fluid from the salivary glands in her mouth, and thus makes tiny bricks. These she builds into the form of a hollow sphere, about the size of a walnut, with a hole in the top through which she lays from 50 to 100 eggs. Others lay their eggs in bunches in the soil and coil around them until they hatch. Mothers may even remain with the young for a few days. The bite of the millipede, unlike that of the centipede, is not poisonous. But the animal has “stink glands” from which a foul-smelling liquid containing the extremely poisonous prussic acid is exuded. This presumably affords an adequate protection against driver ants and birds, the natural enemies. The secretion is so powerful that a couple of millipedes placed in a can kill insects as effectively as a small dose of potassium cyanide.