Published online by Cambridge University Press: 31 May 2012
Factors promoting wing production in aphids have been studied extensively by many workers (Ackerman, 1926; Bonnemaison, 1951; Ewing, 1925, 1926; Lal, 1952, 1955; Shull, 1926-1942; Wadley, 1923; and White, 1946), who advanced theories based on experimental results with different species but generally considered to be applicable to all aphids. La1 (1952, 1953) reviewed this literature. The experiment reported here indicates that the theories previously advanced do not apply equally to all species.