U!.^ 



13. Tail tapering uniformly from in front of anus 



o fastip:atus Th. & Swang., 1936 (s) 



Tail not tapering uniformly from in front of anus ill 



lU. Width over 3.0^ 15 



Width under 2,^% l6 



1$, Ovary one limnophilus de Man, i860 (s) 



Ovaries two japonicus Th, & Swang,, 1936 (s) 



16. Tail length 5.0^~10.05S 17 



Tail length about 20.0^ 18 



17. Terminus dentate, supplements within range of spicula 



denticaudatus Imamura, 1931 (s) 



Terminus not dentate, supplements far anterior to spicvila 

 leptus Th, & Swang., 1936 (s) 



18. Ovaries two, supplements contiguous . . oxycephaloides de Man 

 Ovary one, supplements not contiguous , , oxycephalus de Man 



19. Tails of both sexes long and filiform 20 



Tails of females filiform; male tails, idien known short and 



rounded 23 



20. Length under 1,0 mm infecundus Th, & Swang., 1936 (s) 



Length well over 2.00 mm 21 



21. Supplements not contiguous, 6 or 7. • . . brigdamensis de Man, I876 (s) 

 Supplements contiguous , 22 



22. Supplements averaging about 17. . . paralongicaudatus Micol., 1925 (s) 

 Supplements averaging about 25. . . . longicaudatus Butschli, 187U (s) 



23. Width about 1.5^ 2li 



Width 2.0^ or more 2$ 



2U. Esophagus about 7.0^ . tambo Imamiira, 1931 (s) 



Esophagus about l6.0^ filiformis Bast., 1865 (a) 



25. Lip region set off by constriction 26 



Lip region not set off by constriction. 27 



26, Male tail hemispherical-conoid ,exilis Cobb, 1893 (s) 



Male tail blunt,, ventrally arcuate, , , . dadayi Th. & Swang,, 1936 (s) 



27. Length 1,0 mm. or less 28 



Length distinctly over 1,0 mm 30 



28, Lip region continuous with neck contour 



,,,. , japonicus Th. & Swang,, 1936 (s) 



Lip region set off by slight depression 29 



