PROC. ENT. SOC. WASH., VOL. 71, NO. 3, SEPTEMBER, 1969 397 A SCELIONID WASP SURVIVING UNCHANGED SINCE TERTIARY ( Hymenoptera : Proctotrupoidea ) LuBOMiR Masner, Institute of Entomology, Czechoslovak Academy of Sciences, Praha^ ABSTRACT — Palaeogryon muesebecki, n. gen. and n. sp. ( Scelionidae : Scelioninae), is described from both late Oligocene Mexican amber and recent specimens from Mexico. This is the first evidence in Proctotrupoidea of a species having survived unchanged during the past 30 milhon years. The fact is more surprising since this rehct species constitutes a highly advanced ( apomorphous ) form of Scelionidae. While studying the unsorted proctotrupoid wasps in the United States National Museum in Washington ( 1964 ) I found two specimens from Mexico marked by C. F. W. Muesebeck to constitute a new genus and species of Scelionidae. Two years later when studying Proctotrupoidea from Mexican amber I discovered the same species and genus mentioned above. Closer examination of both the recent and fossil wasps revealed a prefect conspecificity. The identity can be made with certainty due to perfect preservation of the two females embedded in amber. I was able to detect even such minor details as the number of bristles on veins and the finest sculpture of the body ( length of body 0.6 mm.). There is absolutely no difference between the recent and fossil specimens. This is a surprising fact as the new species is by no means an archaic type. The structure of the antennae in particular makes this genus a highly apomorphous form within the Scelionidae ( Scelioninae ) . The Proctotrupoidea from the Mexican amber look generally younger than those of Baltic amber. It seems the climatic changes since the Tertiary of Central America were considerably less pronounced than those of Tertiary Baltic, allowing some species to survive until the modern era. The scelionid wasp described below is the first Tertiary rehc known. In other groups of insects (e.g. termites, Snyder, 1960) the Tertiary relics are known from Mexican amber or at least species that can be claimed to be the direct ancestors of recent species ( Sturte-vant, 1963; Wille, 1959). All these forms are now distributed either in Mexico or in the adjacent areas (e.g., Caribbean). ^Present addre.ss: Pestology Centre, Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia.