The Biology of a Hyperparasite, Euceros frigidus Cress. (Ichneumonidae) and Description of the Planidial Stage

Abstract

For more than a decade the sawfly, Neodiprion swainei Midd., has been a serious defoliator of jack pine, Pinus banksiana Lamb., in the Province of Quebec. In 1955 an intensive research program involving several research officers was initiated at the Forest Biology Laboratory, Quebec, to study the insect. Investigations began near the centre of the infestation at the headwaters of the Gatineau River (47° 55′N., 75° 25′W.). The project dealing with the parasites became the responsibility of the author and constituted approximately 25 pcr cent of the total investigations. Integrated with this project were studies on population dynamics, effect of defoliation on jack pine, and predators of the sawfly with emphasis on the small mammals. The primary object of the parasite studies was to concentrate on the life cycles and descriptions of the immature stages and to publish on each species as sufficient information was obtained. Ultimately, it is planned to publish jointly with other members of the team on the role of parasites in the overall mortality complex of Neodiprion swainei.