Morphology and parasitism of the mature female of Rotylenchulus macrosomus(l)

The mature female of Rotylenchulus macrosomus, hitherto unknown, was discovered in the vicinity of the type locality, and its morphology and parasitism were studied in comparison with R. renifonnis. Morphologically, R. nzacrosomus differed from R. renifomzis in its greater body length, more convoluted body posture, more anteriorly situated vulva, and more pointed tail terminus. R. nlacrosomus was found to reproduce on a number of vegetable crops but, notably, did-not attack Cotton, which i s very sensitive to R. renifomzis. On a common host, soybean, the two species induced a similar reaction, viz., an enlarged endodermal feeding cell within which a feeding tube was formed, and a syncytium comprising more or less intact hypertrophied pericyclic cells, with ce11 Wall breakdown in the region close to the nematode head. The resemblance between the mature females of R. macrosomus and R. borealis is emphasized and the general similarity between these two species also in their male and immature female forms, host preferences, and host tissue reactions is shown. RÉSUMÉ Morphologie et parasitisme de la femelle mature de Rotylenchulus macrosomus La femelle mature de Rotylenchulus macrosomus, non observée jusqu'à présent, a été découverte à proximité du lieu type de l'espèce. Sa morphologie et son parasitisme ont été étudiés et comparés à ceux de R. renifonnis. Morphologiquement, R. macrosomus diffère de R. renifonnis par un corps plus long et plus convoluté, la vulve située plus antérieurement et l'extrémité de la queue plus pointue. R. macrosomus se reproduit sur de nombreuses plantes maraîchères, mais il est à remarquer qu'il n'attaque pas l