VIDEO THEME WEEKS: This week... all things Domestic Silkworm, Bombyx mori. For our second clip, watch a silkworm shed into its final instar, or growth stage. Silkworms have darker tracheal breathing tubes compared to most other caterpillars, which makes the tubes relativey easy to follow as they are shed out through the spiricals. Caterpillars must shed their skins, their old head capsules, their internal breathing tubes, and even their fore and hindgut multiple times as they grow. | The Caterpi