Ecdysis

Ecdysis (from Ancient Greek: ἐκδύω, ekduo, to take off, strip off) is the moulting of the cuticula in many invertebrates. This process of moulting is the defining feature of the clade Ecdysozoa, comprising the arthropods, nematodes, velvet worms, horsehair worms, rotifers, tardigrades, and Cephalorhyncha. Since the cuticula of these animals often forms an inelastic exoskeleton, it is shed during growth and a new, larger covering is formed. The remnants of the old, empty exoskeleton are called exuviae.