157. With a ridge within the last whorl; body whorl faintly keeled 



Polygyra (Polygyra) cereolus (Muhlfeld) 

 No ridge within the last whorl; body whorl sharply keeled 

 Polygyra (Polygyra) septemvolva Say 



158. With strong transverse ribs; about I/4"; east'Central states 



Polygyra (Daedalochila) plicata Say 

 Not so 159. 



159. Umbilical opening wide, showing all of the last volution; about ^Z^'; 



southeastern states 



Polygyra {Daedalochila) pustuloides (Bland) 

 Umbilical opening small or partly covered by the reflected lip 160. 



160. Umbilicus partly covered by the edge of the aperture; about ^Z^'; south' 



central states 



Polygyra {Daedalochila) leporina (Gould) 

 Lip not covering umbilicus; about Y/' to V2" 161- 



161. With a tubercle or transverse ridge far back within the aperture on the 



base of the last whorl 162. 



Not so 163. 



162. With an upright tubercle on the base of the last whorl; central states 



Polygyra {Daedalochila) dorfeuilliana Lea 

 With a transverse tubercle or ridge on the base of the last whorl; Texas 

 Polygyra {Daedalochila) hippocrepis (Pfeiffer) 



163. Teeth well developed; outer tooth on lip with a hook; southeastern states 



Polygyra {Daedalochila) postelliana (Bland) 

 Teeth less well developed; with the parietal callus less elevated; no hook 

 on the outer tooth on lip; southern states westward to Texas 

 Polygyra {Daedalochila) auriformis (Bland) 



164. Aperture much narrowed, projecting scarcely beyond the outline of the 



body whorl; parietal wall with a long, thin, oblique tooth parallel to 



the lip (Many species, of which a few common ones are given here) 



Narrow-mouthed Wood Snails 165. 



Not so 168. 



165. Outer lip not indented 166. 

 Lip indented 167. 



166. Coils narrow and close; epidermis without hairs; lip not partly overlap- 



ping umbilicus; about %"; eastern and central states 

 Stenotrema monodon (Rackett) 

 Coils wider and looser; epidermis with fine hairs; lip usually partly over' 

 lapping umbilicus; almost ^2"' eastern and central states 

 Stenotrema fraternum (Say) 



167. Parietal tooth incompletely overhanging lip, as seen from side view; 



about %"; eastern and central states 

 Stenotrema hirsutum (Say) 

 Parietal tooth completely overhanging lip; about Ys'^; central states 

 Stenotrema stenotrema (Pfeiffer) 



132 



