|
Silk, Silk dress, Silk fabric, Silk dress, Silk scarf |
|
THE SILK WORM The common silk worm produces only one generation during the year where the seasons are defined. In some areas, such as India and China, reproduction is almost continuous. Its natural food is the foliage of mulberry trees. The silk glands consist of two long thick-walled sacs running along the sides of the body, which open by a common orifice - the spinneret or seripositor - on the under lip of the larva. When the larva is fully mature, it proceeds to spin its cocoon, in which it ejects from both glands a continuous and reelable thread of 800 to 1,200 yards in length, moving its head around in regular order continuously for about three days. The filament produced averages 1/1,200 of an inch in thickness. The cocoons average one inch to 1 1/2 inches in length. From ten to twelve days after the completion of the cocoon, the insect is ready to escape. A perfect moth comes forth and the sexes almost immediately couple. In four to six days, the female lays her eggs numbering over five hundred. With their life cycle completed, the moths soon die. Cocoons are boiled in vats With the exception of those selected for reproduction of eggs, the cocoons are treated to preserve them intact. The chrysalis must be killed without damage to the cocoon. The worm spins the cocoon with one continuous thread forming a figure eight. Cutting the cocoon at one end to allow the moth to escape will cut the continuous thread into thousands of short ones.[excerpts from Encyclopedia Britannica] Workers remove the boiled cocoons from the vat and find the end of each
strand of silk. It is then threaded overhead. A single thread of silk
can measure up to 4,000 feet in length. |