ABSTRACT
The stunt nematodes are a broadly distributed group of genera and species having global existence in agricultural soils and uncultivated land. Most species of stunt nematodes are known only from the type locality, are distinguishable by a few minor characters only, and with few exceptions, are poorly known as to their limits of variation and biology. The classification of stunt nematodes presently is unstable and one of the most controversial problems in plant nematode taxonomy. Scanning electron microscopy has produced a major advance in the taxonomy of stunt nematodes by permitting species to be arranged in well-defined groups, based on external cuticular features, particularly head morphology. Excretory pore opposite anterior end of basal esophageal bulb; hemizonid immediately, or a body annule anterior, distinct. Head bulbous, bearing four or five, rarely three or six annules; septum of head framework conspicuously thickened at periphery and central tube.
