Silk is produced by :

Each cocoon of silk worm (Bombyx mori) has about 1000 meter of silk thread. During its short life the female moth lays about three to five hundred whitish eggs. A minute caterpillar larva hatches out from each egg in about 10 days. The larva starts pouring out its sticky saliva through a minute aperture called spinneret located upon the lower lip of its mouth. As it comes out in air the lpuid saliva immediately solidify into a fine silk thread.