A dragonfly is an insect belonging to the order Odonata, infraorder Anisoptera. Fossils of very large dragonfly ancestors in the Protodonata are found from 325 million years ago in Upper Carboniferous rocks; these had wingspans up to about 750 mm (30 in). Today, there are about 3000 species of Anisoptera in the world. Adults are characterised by large multifaceted eyes, two pairs of strong transparent wings, sometimes with coloured patches and an elongated body. Many have brilliant iridescent or metallic colours produced by structural coloration, making them conspicuous in flight. An adult dragonfly’s compound eye has nearly 24,000 ommatidia. Most are tropical, with fewer species in temperate region. They are predators, both in their aquatic larval stage, when they are known as nymphs, and as adults. Several years of their lives are spent as nymphs living in fresh water; the adults may be on the wing for just a few days or weeks. They are fast, agile fliers, sometimes migrating across oceans, and are often found near water. Loss of wetland habitat threatens dragonfly populations around the world. These creatures are represented in human culture on artifacts such as pottery, rock paintings, and Art Nouveau jewellery. They are used in traditional medicine in Japan and China, and caught for food in Indonesia. Dragonflies are symbols of courage, strength, and happiness in Japan, but seen as sinister in European folklore. Credit: Wikipedia.