[Simuliids larvae microsporidans: ultrastructural data (author's transl)]

This work is the summary of our present knowledge about the ultrastructure of Simuliids larvae Microsporidans, including several new data concerning: 1. Pleistophora simulii (Lutz et Splendore, 1904): reticulated or net-like plasmodial envelope, formation of pansporoblastic structures looking like short pipes. 2. Stempellia simulii Maurand et Manier, 1968: plasmodial envelope as Pleistophora simulii, granular-textured polaroplast. 3. Thelohania fibrata (Strickland, 1913): ultrastructural study of the sporogonic sequence nerve done so far. 4. Thelohania bracteata (Stickland, 1913): its relations with Thelohania minuta, T. canningi, Amblyospora bracteata, Pegmatheca simulii. 5. Tuzetia debaisieuxi (Jirovec, 1943): formation of pseudopansporoblasts by the host-cell membrane.