MACROLAIMUS CANADENSIS N. SP. (NEMATODA: PANAGROLAIMINAE), FROM THE FRASS OF THE BARK BEETLE PHLOEOSINUS CANADENSIS SWAINE, 1917, WITH REMARKS ON OTHER SPECIES OF THE GENUS MACROLAIMUS MAUPAS, 1900

Macrolaimus canadensis n. sp., collected from the frass of Phloeosinus canadensis Swaine, 1917, infesting a log of eastern white cedar from Lac Tremblant, Quebec, is described and figured. The new species differs from other members of the genus in having a small, thornlike ventral spine on the spicules and in having comparatively stouter cheilorhabdions.M. aculeatus (Daday, 1905) Thorne, 1937, and M. citri Rahm, 1928, are regarded as species inquirendae. Ruehm's synonymy of M. hamatus Thorne, 1937, and M. crucis of Fuchs, 1938, with M. crucis Maupas, 1900, is not accepted. The systematic positions of M. crucis of Ruehm, 1956, and M. crucis of Fuchs, 1938, are briefly discussed. M. maupasi Hnatewytsch, 1929, is transferred from Macrolaimus Maupas, 1900, to Myolaimus Cobb, 1920.