The present study has been initiated by new species from South America and the deviating classification of sub-groups by several authors. We assume a division of the Parasitiformes into three main groups: 1. Antennophorina Berlese, 1892 s. lat., 2. Margotrichina Karg et Schorlemmer, 2008, 3. Gamasina Leach, 1815. Here, we analyse these groups step by step. Cladograms that are based on autapomorphies and synapomorphies visualize relationships between subgroups. 1. The Antennophorina are divided into the Sejides Berlese and the Trigynaspida Camin et Gorirossi including the Celaenopsoidea Berlese, Cercomegistoidea Trägårdh Fedrizzioidea Trägårdh, Megisthanoidea Berlese and Trigynaspidoidea Camin et Gorirossi. Two new species belong to the Cercomegistoidea and the Fedrizzioidea. A new genus of the Fedrizziidae is erected: Holostethus n. gen. 2. Larval-systematic investigations and comparisons of the chaetotaxy of extremities lead to two novel findings. First, the group of the Microgyniina belongs to the Margotrichina. Second, the Thinozerconina have to be separated from the Uropodina group. Hence, the Margotrichina now comprise the four subgroups Microgyniina, Thinozerconina, Uropodina and Ixodides. 3. The state of art regarding the Gamasina is briefly outlined. We describe two new species of Gamasiphoides - family Gamasiphidae and generate a key for new and known species of the genus.