Chrysocharis laricinellae (Ratz) is a European parasite of the larch casebearer, Coleophora laricella (Hbn.), and was one of several species introduced into eastern North America in the 1930's for biological control. Following their release, C. laricinellae and the braconid Agathis pumila (Ratz.) became established and reduced casebearer poulations drastically (Graham 1949). Both parasites are now being used for biological control of the casebearer in western North America. A. pumila was first released in northern Idaho in 1960 (Denton 1979). C. laricinellae was not intentionally released until 1972 (Ryan and Denton 1973), although it probably became established in certain areas earlier (Ryan et al. 1974). The purpose of this paper is an historical documentation of the early distribution and relative abundance of C. laricinellae, made possible largely because of an extensive, one-time survey in 1977 by entomologists of the USDA Forest Service, Northern Region (Flavell 1979).