Palaeozoic and Mesozoic hemiptera (Insecta)

New species of Triassic Homoptera and Heteroptera from the Brookvale series of New South Wales and Mt. Crosby, Queensland, are described, one homopteron from the Upper Permian of Warner's Bay, N.S.W., and Homoptera previously recorded from Palaeozoic and Mesozoic strata in Australia and elsewhere are reviewed. New illustrations, made from type specimens, are given for some Australian species. Representatives of the family Scytinopteridae, previously known only from Permian strata, are recorded from the Triassic. Two forewings of uncertain affinities, but having venational features similar to hylicids, are ascribed to species in genera placed in a new family, the Hylicellidae. For leaf-hoppers which are regarded as transitional between the Palaeozoic and Mesozoic faunas, a new family, the Stenoviciidae, is proposed, and another new family, the Chiliocyclidae, is proposed for a group of Mesozoic leaf-hoppers of wide distribution. A forewing from the Triassic of Queensland is identified as that of a eurymelid and another as a cicadellid. The earliest undoubted cercopid, so far recorded, is described from the Triassic; a new family, the Eoscarterellidae, is defined to comprise insects of probable cercopoid affinities, and the family Dysmorphoptilidae is transferred to the Cercopoidea. As the genus Palaeontina Butler is considered not to be a homopteron, a new family name, the Cicadomorphidae, is proposed for large Homoptera with cicada-like wings, previously recorded only from the Jurassic of Europe and which formerly have been included in the family Palaeontinidae. A new genus and species belonging to the Cicadomorphidae is described from the Triassic of New South Wales. The relationships of a new family, the Cicadoprosbolidae, and of the Mesogereonidae are discussed and both are considered to be allied to the Cicadidae. Two new psylloids are described and also an aphid, the latter being the first representative of the Aphidoidea to be recorded from Triassic strata. No new fulgoroids are described but problems associated with the determination of fulgoroid venation are discussed. The genus Actinoscytim Tillyard is transferred from the Homoptera to the Heteroptera and together with three new genera ascribed to a new family, the Actinoscytinidae. The family Ipsviciidae, formerly regarded as belonging to the Homoptera is also removed to the Heteroptera. The family Dunstaniidae is reviewed in the light of a re-examination of type specimens. Fossil fragments, poorly-preserved specimens, and wings of uncertain position which have at some time been referred to the Homoptera, are listed, and some are discussed. Possible derivations and interrelationships of the various major groups of Homoptera are indicated by means of a chart.