1. Current address: Department of Medical Entomology, National Institute of Infectious Diseases, Tokyo, Japan
2. Department of Zoology, National Museum of Nature and Science Tokyo, Ibaraki, Japan
3. Forestry and Forest Products Research Institute, Ibaraki, Japan
4. Laboratory of Biomedical Science, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, Kanagawa, Japan