Abstract: The classification of subgenus Larrousius is discussed and the relative importance of their morphological characteristics was compared. The authors stress that the most important taxonomic characteristics is the male aedeagus which varies with the species, while the morphology of the spermatheca segments and the pharyngeal armature are of much importance for female taxonomy. Besides, other morphological characteristics are either useless or of no importance for the classification of subgenus Larrousius. By comparison, P. major Annandale, 1910 and P. major wui Yang et Xiong, 1965 belonging to the subgenus Larrousius, are quite different in their morphological characteristics of pharyngeal armature, spermatheca segments and aedeagus form. Thus it is suggested by the authors that P. major wui Yang et Xiong, 1965 should be raised to species P. wui (Yang et Xiong, 1965) stat. nov. instead of subspecies.