Fairy flies are tiny egg parasites, and there family Mymaridae is the family of the Alpatus Magnimius(0.21 mm., male) the smallest discovered species in the class Insecta. The fairy flies are actually slender wasps. Fairy flies are found worldwide and at great altitude which indicates that the fairy flies are dispersed through the air like dust. The largest of fairy flies have a wingspan of 3mm.
Fairy fly females are larger than male fairy flies. Females are also much better at flying than the males. Fairy flies only have two hairy wings like early insects, and many species swim submerged under the water using their wings as paddles. Mating and egg laying may also occur underwater. An individual of these genera of fairy flies can stay underwater for up to 15 days. They exit the water, climbing onto a the stem of a plant that breaks the surface.
There are 1400 species of fairy flies of and 100 genera. No commonly accepted sub-family been has acknowledged. When collected correctly fairy flies are the most common wasps. Common hosts of fairy flies are eggs of crickets, grasshoppers, beetles, true bugs, cicadas, aphids, lice, flies and aquatic bugs. Cicada eggs are the most common hosts of fairy flies. Pupatation happens inside the egg shell until, usually, until mature larva is in the host egg. Successful bio-control programs involving fairy flies have occurred, notably, to control in insects being pests of the eucalyptus in southern Europe, South Africa, South America, New Zealand. Fairy flies could be a common and helpful and in many eco-systems. Fairy flies are rarely seen, though and, surprisingly little is known about fairy flies. This is an area of entomology where an amateur naturalist could make a significant difference.