Range: Eastern United States. The pupa climbing tree trunk. Then it bursts its horny outer skin and crawls out an adult.] The Silkworm and the Honey-bee have been domesticated since prehistoric times, the former supplying a valuable fiber for clothing and the latter an important article of food. Among the injurious insects a few may be mentioned: the House Fly or Filth Fly, which may carry disease germs on its feet to the food that we eat; the mosquitoes, which transmit yellow fever and malaria, the rat flea, which carries bubonic plague; the weevils, which destroy rice, beans, chestnuts, etc., and the plant lice, or aphids, which, by sucking the juices from ornamental and food plants, are among the most destructive of all insects. There are so many insects in the world that we cannot hope to learn of them all, even if we wanted to do so, but most of us wish to know the names of those that attract our attention, and to know what they do that is important or interesting. There are approximately 400,000 species or kinds of insects known in the world; that is, about three times as many as there are species or kinds of all the rest of the animals in the world put together. This fact should not hinder us from making a start and becoming familiar with the interesting habits of a few of the insects about us. The eggs of the Monarch Butterfly may be collected upon the milkweed and brought in, so that the whole life history or metamorphosis of this beautiful insect, from the egg through the larva or caterpillar stage and the pupa or chrysalis stage to the adult butterfly, may be watched. The larvae or caterpillar must be supplied daily with fresh milkweed leaves. Other butterflies and moths and many other insects may be reared in the same way by supplying the larvae with suitable food. If we should find a caterpillar feeding upon the leaves of a maple tree we should continue to feed it maple leaves if we wish to rear it. Silkworms will eat the leaves of Osage-orange, but they seem to prefer mulberry leaves. Cocoons of moths may be easily collected in winter after the leaves have fallen, and brought in and kept in a cool place until spring when the coming out of the adult moths will be an occurrence of absorbing interest. [Illustration: "A GATHERING OF MONARCHS" Monarch Butterflies resting during migration. The Monarch ranges all over North and South America and it migrates like the birds. Photograph of group in American Museum of Natural History.] The spiders, although not insects, are interesting little animals. See how many types of webs you can find. Mention a few insects which you know to be preyed upon by spiders. Mention one insect that catches spiders and stores them away as food for its young. [Illustration: TRACKS OF THE GLACIER North America at the time of the maximum stage of the Great Ice Age, showing area covered by ice. (After Chamberlin and Salisbury). Photograph used by courtesy of Henry Holt & Co.]