Abstract
The scale insect Toumeyella numismaticum Pettit and McDaniel occurred in small areas of heavy infestation in jack pine, Pinus banksiana Lamb., stands of southeastern Manitoba, where it was present in the same areas every year. The large populations of Formica obscuripes Forel present in the scale-infested areas lessened the effectiveness of the main predator of the scale, the coccinellid Hyperaspis congressis Watson, through interference with the Hyperaspis adults.