Hymenoptera(chalcidoidea)

Chalcidoids are found in all zoogeographic regions and in all habitats from equatorial forests to the northernmost tundra, from deserts to ponds. Despite their omnipresence they remain one of the poorest known groups of parasitic Hymenoptera, partly because of their small size (most are 3-5 mm or less in length), morphological and biological diversity, and numerical abundance. About 3300 nominal genera and 22,500 nominal species have been described, of which about 2000 genera and 18,500 species are considered to be valid (Noyes 1990). The number of species certainly represents only a fraction of the true diversity of Chalcidoidea, and estimates of 60,000-1, 00000 chalcidoid species do not seem to be unreasonable (Noyes 1978, Gordh 1979).