This paper is a contribution of principal investigators of the Alfalfa Subproject supported 
by an International Biological Program (IBP) sponsored grant, NSF Grant No. GB-34718, 
“The Strategies, Principles, and Tactics of Pest Population and Regulation in Major Crop 
Ecosystems.” 
Principal Investigators: 
E. J. ARMBrust — Project Leader, Illinois Natural History Survey and 
Illinois Agricultural Experiment Station 
D. W. Davis — Utah State University 
E. A. Dickason — University of Nebraska 
D. G. Hanway — University of Nebraska 
R. G. Hetcesen — Cornell University 
B. C. Pass — University of Kentucky 
R. L. Prenxowsxi — Virginia Polytechnic Institute and State University 
W. G. Ruesinx — Illinois Natural History Survey and 
Illinois Agricultural Experiment Station 
C. G. Summers — University of California 
EE 
Enlarged view of adult of Sitona species (Coleoptera: Curculionidae). 
