Damselfly nymph skin. Light micrograph of the head and thorax of a shed skin from a damselfly nymph (Coenagrion sp.). This is the ventral (underside). Attached to the underside of the head is an extended mask (top, centre). Three pairs of legs are attached to the thorax (centre) Two jaws used to catch and hold prey are attached to the mask, which extends when prey is detected. The prey is broken up by mandibles after it is drawn back to the mouth. Damselflies undergo incomplete metamorphosis, which involves three stages of development; the egg, nymph and adult stage. The nymph sheds its skin several times before an adult damselfly emerges.