The following are notes on the taxonomies and synonymies, and on the distributions in Canada, of the Nearctic species of leafhoppers of the genus Oncopsis Burmeister. Twenty-one species referable to this genus have been described from the Nearctic region. Seventeen were listed as valid species by Oman (1949), under Oncopsis, Macropsis, and Zinneca. One is probably not a Nearctic species. In the present paper 14 names are considered to be synonyms. This reduces the number of Nearctic species to seven, including one new species described below. Wagner (1949) discussed six species found in Germany. Of these, two were new and the remaining four had been described under a total of 14 names.

A study of the insect inhabitants of the sour cherry orchards of the Niagara district of Ontario was begun in the spring of 1947, ass part of an investigation of virus diseases of stone fruits carried on cooperatively between the Dominion Entomological Laboratory at Vineland Station and the Dominion Laboratory of Plant Pathology at St. Catharines. The virus disease cherry yellows of sour cherry had by that time become prevalent and appeared to be spreading rapidly. The rate and pattern of spread revealed by a survey of orchards suggested that an insect vector may be involved in the dissemination of the virus. The Hemiptera were chosen as the first group for study because most of the known vectors of plant viruses belong to this order.

Studies on the transmission of the virus of little cherry disease in the Kootenay Valley of British Columbia involve the feeding of introduced insects on uninfected cherry trees. Muslin cages slipped over individual branches and tied at both ends were first used to confine the introduced insects but resulted in heavy insect losses. Temperature within the caged area was likely to be excessive, it was difficult to introduce and recover the insects, and insects became entangled in the muslin. A special cage has been designed to overcome these difficulties.

Several blow fly collections were made in the vicinity of Fairbanks between May 28 and June 14, 1948, and one large collection at Anchorage on August 9, 1948. All flies were caught in screen-wire fly traps baited with liver or dead salmon. The material was identified by D. G. Hall, Bureau of Entomology and Plant Quarantine, who also generously provided information concerning the possible importance of the various species of Alaskan blow flies.