Fairyfly

The Mymaridae, commonly known as fairyflies or fairy wasps, are a family of chalcid wasps found in temperate and tropical regions throughout the world. It contains around 100 genera with 1400 species. Fairyflies are very tiny insects, like most chalcid wasps. They generally range from 0.5 to 1.0 mm (0.020 to 0.039 in) long. They include the world's smallest known insect, with a body length of only 0.139 mm (0.0055 in), and the smallest known flying insect, only 0.15 mm (0.0059 in) long. They usually have nonmetallic black, brown, or yellow bodies. The antennae of the females are distinctively tipped by club-like segments, while male antennae are thread-like. Their wings are usually slender and possess long bristles, giving them a hairy or feathery appearance, although some species may have greatly reduced stubby wings or lack wings altogether. They can be distinguished from other chalcid wasps by the H-shaped pattern of sutures on the front of their heads. Fairyflies are some of the most common chalcid wasps, but are rarely noticed by humans because of their extremely small sizes. Their adult lifespans are very short, usually lasting for only a few days. All known fairyflies are parasitoids of the eggs of other insects, and several species have been successfully used as biological pest control agents. The fossil record of fairyflies extends from at least the Albian age (about 100 Mya) of the Early Cretaceous. They are the only chalcid wasp family known from the Cretaceous, and thus are considered the most primitive family within Chalcidoidea. The family Mymaridae was first established in 1833 by Irish entomologist Alexander Henry Haliday. Haliday and two close friends and respected entomologists in their own right, John Curtis and Francis Walker, were influential in the early studies on Hymenoptera in the 19th century. Haliday originally described fairyflies as the tribe 'Mymares' of the family 'Chalcides'. He based his descriptions on the type genus Mymar, described by John Curtis in 1829. Earlier attempts of classification by Walker treated the group as a genus, and classified all other known fairyflies under it as subgenera. Walker (who was infamous for his shortcomings in systematic nomenclature) later conceded to Haliday's classification in a letter in 1839 and requested assistance from Haliday in classifying the chalcid wasps collected by Charles Darwin on his voyage on HMS Beagle. 'Mymares', as well as other 'tribes', were elevated to the family rank (as Mymaridae) by Haliday in 1839. Haliday described fairyflies as 'the very atoms of the order Hymenoptera' and remarked on the beauty of their wings when viewed under the microscope. These characteristics of fairyflies also made them popular to entomologists and microscopists of the late 19th and early 20th centuries. The beautifully mounted fairyfly specimens of the early 20th century English microscopist Fred Enock are possibly the most famous of the collections.