155. 



168. Neck constricted behind spear , , latus Cobb, 1891 (s) 



Neck not constricted behind spear . . . . , 169 



169. Width over 7.5!^J anus almost terminal .... kryg^eri Ditl., 1928 (s) 

 Width under "p.O'oj anus more ventral , . , 170 



170. Lips amalgamated, obscure ..., 171 



Lips prominent, distinct .,,.... . 173 



171. Lip region width one-sixth that of neck base. . obtusus Cobb, 1893 (s) 

 Lip region width one-fourth that of neck base 172 



172. Terminus conspicuously striated .... striaticaudatus Cobb, 1906 (s) 

 Terminus not conspicuously striated . . . , subsimilis Cobb, 1893 (s) 



173. Esophagus tapering uniformly throughout its length 17it 



Esophagus with definite expansion 175 



17U. Eggs twice as long as body width papillatus Bast., 1865 (s) 



Eggs about half as long as body width .... condamni Vanha, 1893 (s) 



175. Tails blunt, vmiformly conoid, about equal in length to anal body 



diameter , 176 



Tail length distinctly less than anal body diameter 180 



176. Length near 3.0 mm obscurus Th. & Swang., 1936 (s) 



Length 1.0—2.0 mm 177 



177. Amphids duplex amylovorus Th. & Swang., 1936 (s) 



Amphids simple 178 



178. Esophagus 18.0^ of total length . . , vitrinus Th. & Swang., 1936 (s) 

 Esophagus 28.0^0— 30.0^5 of total length . 179 



179. Supplements 6 — 8, anterior to spicula . . no thus Th. & Swang., 1936 (s) 

 Supplements more than 30, within range of spicula 

 propinquus Th. & Swang., 1936 (s) 



180. Spear aperture one-third or less of the spear length I8I 



Spear aperture about half the spear length I83 



181. Lips set off by a depression hyalinus 



Lips set off by a constriction 182 



182. Length 2.3 mm. or more alticola Menzel 



Length about 1.3 nirri steineri Th. &. Swang., 1939 (s) 



183. Esophagus 17.0^ of total length ornatus Fuchs, 1930 (frass) 



Esophagus 23.0^— 26.0/g of total length ISU 



I8I4.. Esophagus enlarged at middle perfectus Cobb, 1893 (s) 



Esophagus enlarged anterior to middle . obtusicaudatus Bast., 1865 (s) 



Some of the foregoing species are aquatic in habit, marked (a), vfhile the 

 majority have been reported from soil or humus, marked (s). There is no 

 sharp distinc-tion between aquatic and terrestrial forms and several 

 species have been collected from stream-side and lake-side banks, marked 

 (s or a). Information re-^arding habitat from Goodey, 1951. 



