oes nothing but eat, in that
time consuming many times its weight of food.[33] Then it begins to spin
the material that forms its chrysalis case or cocoon. The outer part of
the case consists of a tough envelope not unlike coarse tissue-paper;
the inner part is a fine thread about one thousand feet long that has
been wound around the body of the worm. This thread or filament is the
basis of the silk textile industry.

[Illustration: _Copyright, 1898, by Nature Study Pub. Co._

SILK INDUSTRY

1. Silkworm Eggs
2. Fourth-stage Worm
3. Pupa in Cocoon
4. Cocoon
5. Male Moth
6. Female Moth
7. Unspun Silk
8. Raw Manufactured Silk
9. Manufactured Silk]

[Illustration: SILK PRODUCING REGIONS]

At the proper time the cocoons are gathered and, if immediately to be
used, are plunged into hot water. This not only kills the chrysalids but
softens the cocoons as well, so that the outer cases may be removed. The
cases removed, the rest of the cocoon is soaked in warm water until the
gummy matter is softened and the fibres are free enough to be reeled. In
the latter process the ends of a number of cocoons, varying from five to
twenty, are caught and loosely twisted into a single strand. The silk
thus prepared forms the "raw silk" of commerce. Sometimes a number of
strands of raw silk are twisted into a coarse thread, thereby forming
"thrown silk." For convenience in handling, both raw and thrown silk
are made into large skeins called hanks, and most of the silk product is
exported in this form.

A given quantity of cocoons yields scarcely more than one-tenth its
weight in good raw silk. The remaining part, consisting of broken fibres
and cases, is shredded and spun into silk thread of inferior quality.
This material, commonly called "husks" or "knubs," forms an important
item in silk manufacture, and much of it is exported to Europe and
America.

[Illustration: SILK PRODUCTION]

According to traditions, not wholly trustworthy, eggs of the silk-worm
were smuggled to India in the head-dress of a Chinese princess. Thence
sericulture slowly made its way westward to Persia, Asia Minor, and the
Mediterranean countries. Wild silk, a coarse but strong product, is
grown in many of these countries, but mainly in China, where it forms an
important export. The Chinese product is commercially known as "tussar"
silk. Of the product of raw silk, about thirty-five million pounds,
China yields about two-fifths, Japan an