Gordius terrestris sp. nov., adult males from Stillwater, Oklahoma, SEM photomicrographs A–C posterior body region, ventral view, note the variation in the shape of tail lobes and postcloacal crescents (PCC) below the cloaca (CL) D tail lobe showing the distinct row of bristles beginning below the postcloacal crescent (PCC) and progressing on the ventral inner side (small arrows) of the tail lobe (TL); and bristles distributed in a circular pattern on the terminal end (large arrow) of the tail lobe E–G variation in the weakly developed polygonal shaped areoles (circles) on the posterior body region of different male individuals; note the branching bristles (arrows) in E. Scale bars: 175 µm (A–C); 75 µm (D); 8 µm (E–G).