153. Ijip rei^ion not set off in any manner 



aculeatus Th. P. Swan?;., 1936 (s) 



Lip rej^ion set off by a constriction Y-jU 



15)U. Length less than 1.0 imn hawaiiensis Cobb, I906 (s) 



Lenr:th well over 3.0 mm Vj$ 



1^^. Spear length twice width of lip region 



intertextus 



Spear length two and one-third times width of lip region 

 . textilis 



1^6. Lip ref2;ion practically continuous with neck conto\ir 1^7 



Lip region set off by depression or constriction I63 



157. Body expanded near anus, tail bulbous . rhopalocercus de Man, I876 (s) 

 Body tapering posteriorly, not expanded 1^8 



1^8. Length about 0.8 mm parvulus Th. &. Swang., 1936 (s or a) 



Length 1.3— U.O mm 1^9 



159. Amphid aperture one-fourth width of lip region 



teres Th. & Swang., 1936 (marine) 



Amphid aperture one-half or more of lip region width I60 



160. Lip region one-sixth width of neck base 



crassiformis Kreis, I92I4 (moss) 



Lip region one-fourth or more of neck base width I6I 



161. Spear length considerably more than lip region width 

 ..... pacificus Cobb 



Spear length about same as lip region width 162 



162. Spear about one-fourth lip region width . . . tritici Bast., 1865 (s) 

 Spear about one-seventh lip region width 

 intermedius de Man, I88O (s) 



163. Lip region more than one-third as wide as base of neck I6I4 



Lip region one-third or less than width at base of neck 166 



I6U. Tails hemispherical ,...,, laticollis de Man, 1906 (s) 



Tails longer than anal body diameter l65 



165. Lips distinct .,,.., brachycephalus Thorne, 1939 (s) 



Lips amalgamated, obscirre . . , , asymmetricus Th. & Swang., 1939 (s) 



166. Length 0.7 mm, or less . . , , 167 



Length 1,0 ram, or more ,.. I68 



167. Lips obscure ............... minimus Steiner, I91I4 (s) 



Lips conspicuous ettersberpensis de Han, 1885^ (s) 



