Collections of aphids on cereal grains and grasses in Manitoba were made during the years 1958-62. The species collected are important because of their possible economic injury to cereal crops and also because several of the species are known vectors of the barley yellow dwarf virus of barley, oats and other Gramineae. Bruehl (1961) listed all known hosts of the virus, mostly determined in greenhouse inoculation trials. He emphasized the importance oi the feeding habits of aphids under natural conditions in the field. In 1962 most species of aphids on Gramineae were present in unusually large numbers in Manitoba, and an excellent opportunity was afforded to obtain records of breeding colonies on 38 host plants, many of them in the Forage Plots of the Department of Plant Science, University of Manitoba. The host plants and aphids are listed in Table I. The aphid species were determined by W. R. Richards, Entomology Research Institute, Ottawa, or by the senior author.