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 are similar to damselflies, but the adults can be differentiated by the fact that the wings of most dragonflies are held away from, and perpendicular to, the body when at rest. Dragonflies possess six legs (like any other insect), but most of them cannot walk well. Dragonflies are some of the fastest insects in the world.

Dragonflies are valuable predators that eat mosquitoes, and other small insects like flies, bees, ants, and very rarely butterflies. They are usually found around lakes, ponds, streams and wetlands because their larvae, known as "nymphs", are aquatic.

Damselflies (suborder Zygoptera), typically being smaller than dragonflies, are sometimes confused with newly moulted dragonflies. However, once a dragonfly moults, it is already fully grown. There are other distinctions that set them apart: most damselflies hold their wings at rest together above the torso or held slightly open above (such as in the family Lestidae), whereas most dragonflies at rest hold their wings perpendicular to their body, horizontally or occasionally slightly down and forward. Also, the back wing of the dragonfly broadens near the base, caudal to the connecting point at the body, while the back wing of the damselfly is similar to the front wing. The eyes on a damselfly are apart; in most dragonflies the eyes touch. Notable exceptions are the Petaluridae (Petaltails) and the Gomphidae (Clubtails). Wikipedia

The largest living odonate by wingspan is actually a damselfly from South America, Megaloprepus caerulatus (Drury, 1782) while the second largest are females of the dragonfly Tetracanthagyna plagiata (Wilson, 2009). The female T. plagiata is probably the heaviest living odonate.[4]

Megaloprepus caerulatus is a damselfly of the Forest Giant family (Pseudostigmatidae), found in wet and moist forests in Central and South America. It has the greatest wingspan of any living damselfly or dragonfly, up to 19 centimeters (7.5 inches) in the largest males. Its large size and the markings on its wings make it a conspicuous species; a hovering Megaloprepus has been described as a "pulsating blue-and-white beacon".[1] (From: Wikipedia)

As an adult it feeds on orb-weaver spiders in the forest understory, which it plucks from their webs. It lays its eggs in water-filled holes in trees; males defend the larger holes as breeding territories. The naiad is a top predator in its tree-hole habitat, feeding on tadpoles and aquatic insects, including the larvae of mosquito species that are vectors of human disease.

M. caerulatus is the only species in genus Megaloprepus. (From )

From Animal-Speak by Ted Andrews:
The keynote for the Dragonfly or Damselfly is The Power of Light.

Both dragonflies and damselflies are very ancient with estimates of their being around for over 180 million years. They have a beautiful, jewel-like color. These bright colors take time to develop, and this reflects the idea that, with maturity, our own true colors will shine forth. This is part of Dragonfly medicine.

For a lot of people it is difficult to tell the difference between a dragonfly and a damselfly. (As noted above) Another clue as to which one you are seeing, is that dragonflies can 'eat on the wing' whereas damselflies will land before eating. Both are known for their fast flight ( up to 30 miles an hour) and daring aerial feats..as though imitating how light itself can be moved and directed. They can even fly backwards! Dragonflies are sometimes called "mosquito hawks". But both damselflies and dragonflies are excellent hunters of flying insects. They can spot movement from their prey forty feet away, and they use their sharp, spiny legs and strong jaws to capture their prey.

Dragonflies and damselflies inhabit two worlds - air and water. In early life they are 'nymphs' and live within water for about 2 years. When they mature, much like a butterfly, they go through their metamorphosis and move into the realm of air.

For those with this totem, it is not unusual for them to be emotional and passionate in their early years, but as they get older, they learn to find balance with greater mental clarity and control. Sometimes it can even indicate that emotions have gotten shut down because of emotional issues in early life. Remember, dragonflies and damselflies are always found around water showing there must be expressions of the emotional and mental together.

Dragonflies are very territorial. They will lay their eggs within their territory near water. These eggs eventually develop into the nymph state culmunating in a colorful transformation after two years. That is very important to recognize this significance and understanding. It may indicate that you are coming into a two year period of transformation, or a need to institute changes that may culmunate in the transformation you desire within a two year period. It is only by examining your life and activities will you find the understanding of its specific role.

Representations within other cultures:
In Japanese paintings, dragonflies and damselflies are often represent joy and new light. To some Native Americans, they represent the souls of the dead. Some stories speak of the time when they were real dragons. Often we think of dragons as being huge, firebreathing beasts, but remember, the fantastic creatures of the Faerie Realm often come in many shapes and sizes. Because of their link to the ancient dragons, dragonflies are wonderful links in working with nature spirits.

In conclusion:
Life is never quite the way it appears. It is always filled with light and color. Dragonfly can help you see through the illusions and allow your own light to shine through because dragonfly brings the brightness of transformation and the wonder of colorful new vision.