A dragonfly is an insect belonging to the order Odonata, the suborder Epiprocta or, in the strict sense, the infraorder Anisoptera. It is characterized by large multifaceted eyes, two pairs of strong, transparent wings, and an elongated body.Dragonflies typically eat mosquitoes, midges and other small insects like flies, bees, and butterflies. They are usually found around lakes, ponds, streams and wetlands because their larvae, known as "nymphs", are aquatic. Dragonflies do not normally bite or sting humans, though they will bite in order to escape, if grasped by the abdomen. They are valued as predators that help control populations of harmful insects, such as mosquitoes. Dragonflies are one of several insects commonly referred to as "mosquito hawks" in North America.
Dragonfly Characteristics
Dragonflies are capable of hovering followed by rapid acceleration. Some nymphs even hunt on land, an aptitude which could easily have been more common in ancient times when terrestrial
Source:
http://en.wikipedia.org/wiki/Dragonfly