1. Biosystematics Unit of the Parasite Biology, Epidemiology and Systematics Laboratory, United States Department of Agriculture, Agricultural Research Service, Beltsville Area Research Center, East no. 1180, Beltsville, MD 20705, USA
2. Department of Environmental Population and Organismic Biology and University Museum, University of Colorado, Boulder, CO 80309, USA
3. Department of Zoology, The Natural History Museum, Cromwell Road, London SW7 5BD, UK