Taxonomy of some species of Anguina Scopoli, 1777 (sensu Brzeski, 1981) forming galls on Gramineae: value of diagnostic characters and present status of nominal species.

SUMMARY Morphological and biometrical studies of species of Anguina (sensu stricto) causing galls on Gramineae, as represented in two nematode collections at Harpenden, England, contiied that species are often difficult to distinguish apart from their hosts. Re-examination of characters used to separate species, supported in part by statistical analyses, showed that not al1 these characters had value at specific level. For example, relaxed body form (habitus) of females, structure of genital tract, and number of flexures of gonads are not useful below generic level. Shape of tail tip (both sexes) and direction of heat-relaxed curvature of males are among the most useful features; whereas, body length (L), details of œsophagus, V-value, form of spicules and gubernaculum and, possibly, presence of a knob of vestigial tissue on post-uterine sac may help to separate some species. Published evidence suggests that populations in the studied group are usually specific to one or two host genera, and may be a complex of host races within a few closely related species. A. tritici, A. agrostis, A. graminis and A. jimesta are accepted as valid. The definitive description used by Steinbuch (1799) in naming A. tritici was that of Roffredi (1775), therefore the type locality is in Piedmont, North Italy and not Germany. A population from Dactylis glomerata is deemed conspecific with A. graminis; populations from Puccinellia maritima and Holcus mollis are considered undescribed species. Species not included in the study are reviewed from the literature. A. phalaridis (Steinbuch, 1799) Chizhov, 1980 is designated species inquirenda; most others listed by recent reviewers are accepted pro tempore. The poor condition of many specimens in slide collections is,