Archival inkjet print mounted on aluminium composite with custom made wooden frame and museum glass Scientists studying the stoneflies of the Northern Hemisphere have from the start identified two main types: one with typically predatory nymphs and yellow or green adults with reduced mouthparts, and one with nymphs feeding on al-gae or detritus, and brownish adults with normally developed mandibles. Klapálek (1907) coined the terms Setipalpia and Filipalpia for these respective types. In the same year, Enderlein in-troduced the terms Systellognatha and Holognatha for approximately the same groups of stoneflies. Since the 1970s, the latter terms (with Holognatha replaced by Euholognatha Zwick 1973) have replaced Setipalpia and Filipalpia in the scientific literature. Current research confirms Systellognatha as a natural group deriving from a common ancestor (‘monophyletic’). Euholognatha, however, may be an artificial ‘rest group’. In the case that future research establishes this, the concept Euholognatha will also become obsolete.