1. USDA Forest Service, Rocky Mountain Research Station 860 North 1200 East Logan UT 84321 U.S.A.
2. Biological Control and Spatial Ecology Lab Université Libre de Bruxelles 50 Avenue F. D. Roosevelt 1050 Brussels Belgium
3. Department of Entomology University of Wisconsin 1630 Linden Drive Madison 53706 U.S.A.