This family was only recently reported from the New World. Yoshimoto recorded 1 new extant species from the Nearctic region (1978a) and 6 extinct species in 3 genera from Canadian amber (1975). Boucek (1993b) reported 4 extant Nearctic species in 3 genera, one of which, Dipriocampe diprioni, was introduced and established in the Nearctic from Europe. He also mentioned an undescribed species from Montana. Generally tetracampids are regarded as intermediate between pteromalids and eulophids. The males of many species have 4 segmented tarsi (typical of the Eulophidae), while females always have 5 (as in the Pteromalidae). The antennae of both sexes are as in the Pteromalidae. Boucek and Askew (1968a) provided a world catalog of the family and revisionary work was published by Sugonyayev (1971) and Boucek (1988, 1993b). Boucek (in Gibson, et al. 1997) keyed the North American genera.

STATISTICS: This is a small family with about 15 genera and 50 species worldwide. There are 4 extant Nearctic species in 3 genera.

BIOLOGY: Unknown for New World species. Palearctic species attack eggs of Chrysomelidae and Diprionidae, and some attack larvae of Agromyzidae.

DISTINGUISHING CHARACTERS: Female and male tetracampids may be separated from pteromalids by the small, straight foretibial spur of the former, while the latter has a long, bent spur. Male tetracampids of some species may have all tarsi 4-segmented. Pteromalids very rarely (Macromesinae) may have the midtarsus 4-segmented, but this is in the females only. Both sexes of tetracampids differ from eulophids in having 11 or 12-segmented antennae (eulophids with at most 10 segments).

COLLECTING: We have collected a few specimens of this family in eastern deciduous forests using sweepnets and a Malaise trap. They are exceedingly rare.

DISTRIBUTION: This family occurs worldwide, but only 4 Nearctic species are known. A species from Cuba and Puerto Rico is also known.