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However, because of ecological adjustments or for obscure reasons, the largest number of species does not always indicate the region of origin.Examples of medium-specialized genera are Glyptotermes, Coptotermes, Schedorhinotermes, Microcerotermes, Amitermes, Termes, Odontotermes, s. str., and Nasutitermes. It may also be concluded that some ancestral medium-specialized genera now extinct were replaced by specialized endemics. Modern relatives of these unknown medium-specialized genera are Promirotermes, Paracapritermes, Capritermes, Angular iter mes, and Subulitermes. In some instances an ancestral genus may be very close to or identical with the modern relative. For instance, Schedorhinotermes is probably very similar to the ancestral genus that gave rise to the neotropical specialized genera, Rhinotermes, Dolichorhinotermes, and Acorhinotermes, and might thus be considered a medium-specialized genus that was eliminated in the Neotropical region by its own specialized descendants.Specialized endemic genera are those that arose from mediumspecialized genera. These genera are thought to be confined to one region because of climatic or geological barriers at the time of their origin.

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Mus.eum of Natural History. INTRODUCTION The origin and dispersal o.f numerous higher taxa of termites by mid-Cretaceous times have been postulated from present geographical distributions and the existence of fairly advanced types in early to middle Tertiary deposits (Emerson, I955, NISS). With the exception of a few extinct genera, the Oligocene termite fauna of Baltic amber includes several genera that are characteristic of present warm temperate climates of Europe and Asia. A recently discovered tropical termite fauna in Mexican amber o.f Oligocene-Miocene age is generically closely similar to the living fauna of the same region (Emerson, NISS). Heretofore, the ea.rliest known fossil termites were found in Eocene deposits of North America, Australia, and Europe. The few specimens of Eocene age belong to the Mastotermitidae (Emerson, I965) and Kalotermitidae (Emerson, MSS), but early Oligocene fossils from several deposits including Baltic amber belong to. the Hodotermitidae, Mastotermitidae, Kalotermitidae, a.nd Rhinotermitidae. The author and others, have. considered the fauna of Baltic amber to be of upper Eocene age (Emerson, I955), but the general concensus now places this fauna in the louver Oligocene. The lack of the most advanced Termitidae from early Tertiary strata is probably due to the general scarcity or absence of this family in temperate climates in the northern hemisphere, and it is predicted that abundant fossils from tropical regions will prove the existence of numerous advanced genera of Termitidae in Cretaceous times. Indeed the tropical fauna, of Mexican amber on the Oligocene-iiocene border proves the presence of living genera of various families that include the Termitidae at that time (Emerson, MSS). The discovery of a fossil termite wing from late Early Cretaceous or early Late Cretaceous (Cenomanian) associated with a, warm temperate flora in Labrador is a considerable extension of accurately determined specimens of the order Isoptera backward in geological This investigation was supported by the National Science Foundation