Damselfly nymph (Coenagrion sp.). Head and thorax of a damselfly nymph. Attached to the underside of the head is a folded mask. Its wings are located on the top of the thorax and are underdeveloped. The legs are also underdeveloped. The abdomen is at far right. 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.