he 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.]

[Illustration: THE KING OF THE NORTHLANDS]

GEOLOGY

_Finds tongues in trees, books in the running brooks,
Sermons in stones, and good in everything._
--_Shakespeare, As You Like It._

The Structure and History of the Earth

There is nothing eternal about the earth except eternal change, some one
has said. It requires only a little looking about us to see that this is
true. The earth is not as it was in the past. Every shower of rain
changes or modifies its surface. And many other and some very great
changes have occurred during the past few millions of years. During one
age, the coal was formed of plants that grew luxuriantly on the earth's
surface. At one period in the development of the earth there were many
kinds of invertebrate animals, but no animals with backbones. Later, the
vertebrates appeared. At one time the whole Mississippi Valley was under
the water of the sea. ("The Story of Our Continent," by N. S. Shaler.
Ginn & Co.). These statements suggest just a few of the things that have
been going on in the history of the earth. By the study of Geology we
can learn much more about it, and we should supplement our study of
books with the more important actual observation of conditions
out-of-doors. To those living in that part of North America, which is
shaded in th