Infective larvae of Cercopithifilaria species from ticks collected from the Japanese serow. (A–F) Type A larva. A. Anterior part, right lateral view. Female genital primordium, arrow. B. Head. C. Oesophageal-intestinal junction. D. Tail, right lateral view at anus. E. Caudal end, ventral view. F. Caudal end, left lateral view. (G–I) Type B larva. G. Tail, right lateral view. H. Caudal end, lateral view. I. Caudal end, ventral view. (J–M) Type C larva. J. Anterior part, right lateral view. K. Tail, left lateral view. L-M. Caudal end, ventral view. (N–S) Type D larva. N. Anterior part, right lateral view. O. Oesophageal-intestinal junction. *Male genital primordium. P. Tail, right lateral view at anus; ventral view at the end. Q. Caudal end, right lateral view. R. Caudal end, ventral view. S. Caudal end, left lateral view. (T–X) Type E larva. T. Anterior part, left lateral view. Cervical swelling, arrowhead; female genital primordium, arrow. U. Head. V. Tail, right lateral view. W. Caudal end, lateral view. X. Caudal end, ventral view. Scale bars: micrometres.