This is a relatively minor family in terms of numbers or biological diveristy. All Nearctic species are believed to be parasites of gall-forming Hymenoptera. Hanson (1992) revised these species and provided a key to them, and later he summarized the knowledge for Nearctic species (in Gibson, et al. 1997).

STATISTICS: Number of world species: 70 (16 Nearctic); number of world genera: 2 (1 Nearctic).

BIOLOGY: Hanson (1992) summarized the known host records of all Nearctic species. In the Nearctic most are associated with cynipid galls on oak. One species is known from a cynipid gall on rose, and several others have been reared from cynipids in asters. One species attacks a pteromalid gall-former on blueberry. According to Boucek (1988) extralimital ormyrids may parasitize gall-forming Diptera and some species develop in figs perhaps as parasitoids of fig wasps.

DISTINGUISHING CHARACTERS: Ormyrids may be separated from other families by the fairly recognizable habitus, with hindcoxae several times larger than the forecoxae and the stigmal vein reduced as in most of the torymids. Ormyrids are distinguished from torymids by the mesepimeron being solid and usually polished (torymids with the mesepimeron divided either by a sulcus or pit and the lower half often sculptured), by the propodeum projecting laterally over the base of the hindcoxa (in torymids the propodeum does not project laterally), and by the prepectus being very much smaller than the tegula (in torymids the prepectus is subequal to the tegula). The ormyrids also are characterized by the metasoma which has coarsely pitted sculpture although these pits are sometimes obscure, and the ovipositor, which is not exserted.

COLLECTING: Specimens of this family are sometimes taken in general sweepings. They may be reared from cynipid galls on oak.

DISTRIBUTION: This family is found mostly in the Northern Hemisphere.