ABSTRACT
The larvae are aquatic and very different in appearance from the adult. (See Fig. 7.2 for general body form of larva damselfly; Fig. 7.3 for a larval dragonfly.) Their heads are large, with distinct mouthparts, fitted for their predacious life. The labium is modified to form a "labial mask," a large ventral structure on the head that shoots outward in front of the head to capture prey. When the mask is withdrawn, the captive creature is stuffed between the waiting mandibles and devoured. External wing pads are evident during the later larva stages. Respiration is by means of either external gills, located at the tip of the abdomen in damselfly larvae, or rectal gills, located internally in the rectal chamber in dragonfly larvae. Water for respiration in the latter case is taken into the rectum by muscular expansion of the cavity. Contraction expels the deoxygenated water. When violently contracted, a threatened dragonfly larva is able to escape from a predator by jet propulsion.
