We are grateful to M. V. L. Barclay (BMNH), J. Frisch (MfN), O. J├Ąger (MTD), A. Mantilleri (MNHN), P. D. Perkins (MCZ), K. Schneider (ESUH), A. Solodovnikov (ZMUC), E. Sprecher-Uebersax (NMB), H. Viljanen (FMNH-UH), L. Zerche and L. Behne (SDEI) for the opportunity to study specimens in their care. This project would not have been possible without funding, development of a cooperative agreement, support, encouragement and understanding provided by T. Walters and A. Redford (USDA APHIS PPQ Science and Technology, Identification Techonology Program), J. Cavey (USDA APHIS PPQ), C. Mitter, J. Smith, T. Hammond (Department of Entomology, University of Maryland). Systematic Entomology Laboratory (USDA) provided space, equipment and logistic support. J. Cavey, S. Clark (M. L. Bean Museum, Brigham Young University, Provo, UT), and N. Woodley (Systematic Entomology Laboratory, USDA ARS) kindly reviewed various parts of preliminary versions of this tool and provided valuable suggestions. Mesa Schumacher (Washington, DC) produced an illustration of morphological features of Diabrotica.