SMITHS,HD OBSERVATIONS ON CITRUS BLACKFLY PARASITES IN INDIA AND MEXICO AND CORRELATED CIRCUMSTANCES

In Mexico during the spring of 1950, four imported species of parasitic Hymenoptera (Amitus hesperidum Silvestri, Prospaltella smithi Silvestri, P. clypealis Silvestri, and P. opulenta Silvestri) were placed on populations of their natural host, the citrus blackfly, Aleurocanthus woglumi Ashby. Their artificial distribution and establishment throughout areas in which the host species was extremely abundant and the observed adjustment of each to its host, to its competitors, and to distinctive regional environments revealed physiological and ecological factors that determined the dominance of one species over another. These factors and the circumstances of their occurrence during 1948 to 1953, inclusive, as reported by Herbert D. Smith, Entomologist of the United States Department of Agriculture, are reviewed and amplified. © 1969, Entomological Society of Canada. All rights reserved.