Fifty-two fossils of megalyrid wasps from various collections of European amber were examined. A male neotype for Prodinapsis succinalis Brues and a female neotype for P. minor Brues are designated. The two species are redescribed and illustrated from Eocene and Oligocene amber, and males are tentatively distinguished by the length of their forewing. Three new species are described: P. pumilio Perrichot & Perkovsky n. sp., from a single female preserved in upper Eocene Rovno amber (Ukraine); P. janzeni Perrichot n. sp., from three males in Eocene Baltic and Rovno amber; and P. oesiensis Perrichot n. sp., from a single male preserved in lower Eocene French amber. A key for the identification of the five species of Prodinapsis is provided. Megazar elegans Perrichot n. gen. and n. sp., and Megalava truncata Perrichot n. gen. and n. sp., are described from Albian French and Spanish amber, respectively, and are placed in a new tribe Megazarini Perrichot n. tribe, which is characterized by the mesothoracic spiracle not being surrounded by pronotal cuticle posteriorly, the inner margin of the metathoracic trochanter, femur, tibia, and first two tarsomeres having comblike spines or stiff setae, the forewing with M Cu being tubular, the basal segment of Rs being very long, and a narrow medial cell [1M]. The following new fossil genera and species are also described and illustrated: Ukrainosa prolata Perrichot & Perkovsky n. gen. and n. sp., from Eocene Rovno amber; Rubes bruesi Perrichot n. gen. and n. sp. from Eocene Baltic amber; Megallica parva Perrichot n. gen. and n. sp., from upper Albian amber of France; and Valaa delclosi Perrichot n. gen. and n. sp., from lower Albian amber of Spain. A second specimen of Megalyra baltica Poinar & Shaw is illustrated from Baltic amber and discussed. A key for the identification of all known fossil and extant genera is provided. The new fossils extend significantly our knowledge of the evolutionary history of Megalyridae sensu stricto (i.e., excluding Cleistogastridae) that hitherto comprised eight modern and two extinct genera. They also emphasize the relictual distribution of the family that is now mainly restricted in tropical and austral regions, while it obviously occurred widely in ancient forests of the northern hemisphere during the Mesozoic and Cenozoic era.