SUMMARYA virus causing maize wallaby ear disease was transmitted experimentally byCicadulina bimaculatato fourteen species of monocotyledonous plants. It was also transmitted byNesoclutha pallida, and by grafting. The symptoms obtained resemble closely those reported for maize leaf gall disease in the Philippines and maize rough dwarf virus in Italy and Israel.About 85% ofC. bimaculatacaught in the field carried maize wallaby ear virus (MWEV), and many of their progeny were viruliferous even when not allowed access to infected plants. The proportion of infective individuals in clones bred for nine generations from selected non‐transmitting adults decreased from 85% in the first nymphs to less than 1%; such individuals were difficult to rear, as their fecundity and longevity decreased greatly.N. pallidatransmitted MWEV after injection with partially purified extracts of infected plants.Spherical particlesc.85 nm in diameter were found in the salivary glands of viruliferousC. bimaculata, but not in those of non‐transmitting individuals. The particles occurred in tubules in the cytoplasm and each had a densely stained corec.50 nm in diameter. Particles similar in size to the core were found in extracts of infected but not uninfected maize, and in extracts of viruliferous but not in non‐viruliferousC. bimaculataandN. pa