Dragonflies and Damselflies belong to the Order Odonata. Odonata are said to be hemimetabolous, or undergo an "incomplete" or "gradual" metamorphosis. Dragonflies and damselflies are semi-aquatic insects. Odonates have 3 stages in its life cycle, viz., egg, nymph and adult. The Odonata are known to be ancient insects. The earliest fossils so far discovered come from Upper Carboniferous sediments.
Dragonflies and Damselflies are very beneficial and important for maintaining the trophic balance in aquatic ecosystems. They are carnivorous throughout their life, mostly feeding on smaller insects. Both adult and immature stages are predacious. Adult dragonflies catch hold of their prey with their legs when they are on the wing.