This family is known from 9 species which are all in the genus Palaeomymar Meunier. They occur worldwide, and specimens are known from amber in the Old and New Worlds. This family is included in the handbook because undescribed species are now known from the Nearctic. In the past, the family was thought of as an "aberrant member of the Mymaridae" (Annecke and Doutt 1961), but its true position in the Chalcidoidea was open to speculation. Current mymarid researchers feel that mymarommmatids are definitely not mymarids, but resemble them only through convergence and are most probably their sister group. Most recently Gibson (1993) placed Mymarommatidae in its own superfamily. We treat the family in this manual because of its easy confusion with Chalcidoidea. The distinguishing characters of the family are a 2-segmented petiole (other chalcidoids have a 1-segmented petiole or are indistinctly petiolate), forewing with a reticulate surface (smooth in other chalcidoids) and a marginal fringe of long setae, face triangular in frontal view with mandibles not meeting (round to square in other chalcidoids, occasionally approaching an inverted triangle in a few species and with mandibles meeting except for a few eulophid species), and the metanotum and propodeum without a visible suture between the sections (chalcidoids with a suture).

The biology of the group is unknown. Gibson (1993) stated that a specimen was reared from a bracket fungus. Based on their extremely reduced size (0.3 mm or so), it is possible that they are egg parasites. They are generally quite rare, but have been collected in numbers a few times. Their reduced size may also explain why they are seldom collected. Huber (1986) reviewed the literature of the group, and Gibson (1993) updated it.