ULTRASTRUCTURE OF POSTERIOR SILK GLAND-CELLS AND LIQUID SILK IN INDIAN TASAR SILKWORM, ANTHERAEA-MYLITTA DRURY (LEPIDOPTERA, SATURNIIDAE)

The ultrastructural characteristics of the posterior silk glands of th e mature Antheraea mylitta (Lepidoptera : Saturniidae) larvae were cla rified. Fibroin globules containing a small dense mass of fibroin fibe rs are produced in Golgi vacuoles, and released from the apical surfac e into the lumen by exocytosis. Bundles of microfilaments, which serve as a dynamic skeleton, are well developed. Numerous autophagosomes or iginating from mitochondria accumulate in both basal and apical ends o f the gland cell; the degenerated materials are released in the baseme nt membrane and into the gland lumen, respectively. These materials in vade the central fibroin column, leaving digested vacuoles in the fibr oin cocoon filament. Ours may be the first finding of this rare phenom enon in which the degenerated lysosomes originated from mitochondria i n both liquid silk in the lumen and cocoon filament.