Page:Popular Science Monthly Volume 50.djvu/519

Rh and crustaceans. Each arthropod has the body composed of rings placed end to end and bearing jointed appendages, and in the myriapods each ring and its appendages can be plainly seen, whereas in the higher forms of the branch many of the rings are so combined as to be very difficult to make out.

Full forty kinds of myriapods occur in any area comprising one hundred square miles in the eastern United States. About twenty-five of them go by the general name of "thousand-legs," as each has from forty to fifty-five cylindrical rings in the body, and two pairs of legs to each ring. The other fifteen belong to the "centiped" group, the body consisting of about sixteen flattened segments, or rings, each bearing a single pair of legs. When disturbed, the "thousand-legs" always coils up and remains motionless, shamming death, or "playing ’possum," as it is popularly put, as a means of defense; while the centiped scampers hurriedly away and endeavors to hide beneath leaf, chip, or other protecting object. All those found in the Northern States are perfectly harmless, the true centiped, whose bite is reputed much more venomous than it really is, only being found in the South. True, some of the centiped group can pinch rather sharply with their beetle-like jaws, and one, our largest and most common species, a brownish-red fellow about three inches long and without eyes, can even draw blood if its jaws happen to strike a tender place. When handled, it always tries to bite, perhaps out of revenge for the abominably long Latin name given it by its describer. In fact, the name is longer than the animal itself—Sco-lo-po-cryp-tops sex-spi-no-sa being its cognomen in full. With such a handle attached to it, who can blame it for attempting to bite? Yet to the scientist up on his Latin each part of the above name bears a definite and tangible meaning. All the myriapods found in the woods and fields feed upon decaying vegetation, such as leaves, stems of weeds, and rotten wood, and in winter three or four species can usually be found within or beneath every decaying log or stump. One species with very long legs is often found in damp houses or in cellars. It is sometimes called the "wall-sweeper," on account of its rapid, ungainly gait, and is even reputed to prey upon cockroaches and other household pests.

Spiders, which do not undergo such changes as do most of the common, six-footed insects, winter either as eggs or in the mature form. The members of the "sedentary" or web-spinning group, as a rule, form nests in late autumn, in each of which are deposited from fifty to eighty eggs, which survive the winter and hatch in the spring, as soon as the food supply of gnats, flies, and mosquitoes appears. The different forms of spiders' nests are very interesting objects of study. Some are