This is a family of fairly characteristic appearance which, once learned, makes the group easy to recognize. Heraty (1985) published a key to Nearctic genera of the family and recently updated this (in Gibson, et al. 1997). Two Nearctic subfamilies are recognized:

Oraseminae: This family contains 16 Nearctic species in the single genus Orasema and was last revised by Gahan (1940). According to Heraty (1985) Gahan's work must be regarded as "an initial treatment."

Eucharitinae: There are 16 Nearctic species in 5 genera. he group was last revised by Heraty (1985) who provided additional information on the the New World species of Pseudochalcura in 1986.

STATISTICS: Number of world species about 400 (32 Nearctic); number of world genera about 50 (6 Nearctic) (world figures from Heraty 1995).

BIOLOGY: All species are believed to be parasitic upon mature larvae or pupae of ants. This family has mobile, planidial 1st instar larvae which are initially free-living. Eggs are laid in large numbers on plant parts and the planidial larva either waits on the leaf or falls to the ground (depending on species) awaiting a passing ant. Once attached to an ant, the larva is taken back to the nest where it attaches to any available ant larva. The wasp waits for the ant to reach prepupal or pupal stage before it begins to feed. (See also information under biology for Perilampidae.)

DISTINGUISHING CHARACTERS: Eucharitids have a characteristic habitus: the pronotum is hidden in dorsal view by the humped-up scutum (i.e. pronotum essentially vertical in profile), and the metasoma is laterally compressed, rudder-like, and on a distinct petiole. Additionally, both sexes may have projections (often extremely developed) from the posterior of the scutellum and some males may have the antennal segments branched. Notauli are present.

COLLECTING: Eucharitids are uncommonly collected, but they are not rare. Generally a few may be taken in any meadowy situation. Occasionally they appear in swarms where they may be collected by the hundreds. These are mating swarms and are usually closely associated with the ant nest from which the parasites are emerging. In addition to the immediate swarm, nearby plants may be covered with ovipositing females. These aggregations occur on warm, sunny days, and are fleeting in nature. They may last only the day. It is possible to collect hundreds of specimens one day and not see another for years.

DISTRIBUTION: Eucharitids are confined largely to tropical and warm areas of the world.