Dragonfly exuvia -
Exuvia (plural exuviae) means the cast-off outer skin of an arthropod after a moult. Emergence is a spectacular event, and usually takes half an hour or so. Freshly emerged dragonflies are ghost-like, with shiny wings and their bodies lacking in pigments. The body and wings harden over the next few hours, during which time they cannot move so, for safety, they normally emerge between dusk and dawn. It can take up to two weeks for a dragonfly to reach sexual maturity, during which time there is a transition to adult colouration.
Unlike butterflies, dragonflies lack a pupal stage in their development, so when the adult is ready to emerge, the larva has to crawl up onto the land, plant stem, or tree and then shed its skin one last time to become an adult. The shed larval skin is left in place, and you can look for these around the artificial ponds in LNEC (Lion’s Nature Education Park in Sai Kung), or near any marshy area, or waterway.