Page:Popular Science Monthly Volume 3.djvu/683

Rh is elongated, and its different parts, that we found so difficult to distinguish, are very much changed. If we examine in detail all the organs just now indicated, even to the nervous system, we shall find modifications not less striking.

But these are not the strangest changes that have occurred. There are others which still more arrest our attention; they are those which relate to the production of a new generation.

All caterpillars are neuters—that is to say, there are no males or females among them. They have no apparatus of reproduction. These organs are developed during the period that follows the formation of the chrysalis while the animal is motionless, and seemingly dead. Marriages occur at the coming out from the cocoon, and, immediately after, the female lays her eggs, averaging about 500 (Fig. 13). This



done, she dies, the male ordinarily dying first. It is a general law for insects; the butterfly of the silk-worm does not escape it. It is even more rigorous for him than for his brethren that we see flying from flower to flower. From the moment of entering the cocoon, the silk-worm takes no nourishment. When it becomes a butterfly, and has assured the perpetuity of the species, its task is accomplished; there is nothing more but to die.

Such, briefly, is the natural history of the silk-worm. It remains to trace rapidly its industrial history.

Whence came this insect? What is its country and that of the mulberry—for the tree and the animal seem to have always travelled side by side? Every thing seems to indicate that China—Northern China—is its point of departure. Chinese annals establish the existence of industries connected with it from those remote and semi-fabulous times when the emperors of the Celestial Empire had, it is said, the head of a tiger, the body of a dragon, and the horns of cattle. They attribute to the Emperor Fo-Hi, 3,400 years before our era, the merit of employing silk in a musical instrument of his own