The Trichogrammatidae are a family of tiny wasps in the Chalcidoidea that include some of the smallest of all insects, with most species having adults less than 1 mm in length. The over 840 species are in about 80 genera; their distribution is worldwide. Trichogrammatids parasitize the eggs of many different orders of insects. As such, they are among the more important biological control agents known, attacking many pest insects (esp. Lepidoptera).
They are not strong fliers and are generally moved through the air by the prevailing winds. Their forewings are typically somewhat stubby and paddle-shaped, with a long fringe of hinged setae around the outer margin to increase the surface area during the downstroke. Males of some species are wingless, and mate with their sisters inside the host egg in which they are born, dying without ever leaving the host egg.