Morphological features of adult specimens of Ascaridia hermaphrodita and A. platyceri (Nematoda: Ascaridida), parasitizing parrots (Psittaciformes), were studied for the first time using scanning electron microscopy. The morphology of A. hermaphrodita, the type species of Ascaridia, coincides fully with the generic diagnosis. The shape of the labial inner structure (two spoon like projections), cervical alae and spicule with cuticular wings were typical for this species. A. hermaphrodita has been found in the Czech Republic for the first time in a new host, Amazona pretrei, from Brazil. The morphology of Ascaridia platyceri does not correspond with the generic diagnosis in all aspects, as some variation was found, mainly in the presence of interlabia, small teeth in the inner ribbon of the lips and long lateral alae. These morphological characteristics in other species of Ascaridia are discussed. The generic diagnosis is to include the statement "interlabia very rarely present".