Embryonic development in Muga Silkworm, Antheraea assamensis Helfer (Lepidoptera: Saturniidae)Abstract : Chronological variations during embryonic development of normal eggs of Antheraea assamensis Helfer were recorded from 24 h to till hatching. During 10-16 h of the embryonic development, the ventral plate is formed and by 24 h trough shaped embryonic premodium floats in yolk and the protocephalon and protocorn are separated by transverse furrows. After 96 h the embryo became C-shaped. Although, mouth parts are yet not developed completely but they were at the advance stage of development. The thoracic region is clearly divisible into three thoracic segments. After 120 h, organogenesis in embryo takes place. The antennae bear segments and head region was detachable into three segments. The head capsule formation completed in after 144 h and mouth parts got matured. Three segmented antennae with antennal setae, the mandibles and labrum are well developed. After 168 h old, mandible become selerotised and pigmented at distal ends. Larval eyes appear as six brown spot on either side of head. The spiracles are clearly visible on the sides of the body. Fully developed muga silkworm larva comes out from the egg cell after 8th day of oviposition rupturing the anterior part of egg shell by the mandibles.