A new genus and species of the family rhabdolaimidae (nematoda), with descriptions of two known species and taxonomic discussion.

A new genus, one new and two known species belonging to family Rhabdolaimidae are described and illustrated. Mediolaimus n. gen. is characterized by small-sized body; papilliform outer labial and cephalic sensilla; long, tubular stoma with stegostom having relatively larger dorsal and smaller sub ventral denticles at same level; cylindrical pharynx with expanded basal bulb having thickened lumen; didelphic gonad having outstretched ovaries; elongate-conoid tail with hemispherical terminus without mucro or spinneret and caudal glands obscure. Mediolaimus obtusicaudatus n. gen. n. sp. is characterized by stoma with a relatively larger dorsal denticle and two fine subventral denticles at same level; amphidelphic reproductive system with outstretched ovaries; tail elongate conoid with smooth hemispherical terminus and absence of male. Rhabdolaimus terrestrisde Man, 1880 and Udonchus tenuicaudatusCobb, 1913 are described with additional details. The inter population variations are discussed in the latter species along with a detailed note on the status of Rhabdolaimidae and its proposed placement under superfamily Rhabdolaimoidea of suborder Campydorina.