The homology concept and its recognition criteria are introduced and discussed, with the importance of transformational (primary) homology assessment in phylogenetic analysis emphasized. We use an ontogenetic approach to explore the setal transformational homology in polychaetotic entomobryid genera (Collembola), where tergal chaetotaxy is usually the most informative character for taxonomy. The postembryonic development of setae on terga of three species in the Sinella-Coecobrya group, Sinella curviseta, Coecobrya tenebricosa and C. aokii are studied following Szeptycki’s principle. Different chaetotaxic patterns of each tergite are homologized and classified for more than 50 species of the two genera. The taxonomical significance of chaetotaxy of abdomen V, which has been rarely studied, is evaluated and affirmed here. The system presented here is a revised and updated from Szeptycki’s system.