The history of the study of the Tetrigidae from the eighteenth century up till today is given. The different parts of the body, that can be used in systematics and in the identification of these insects are described (fig. 9-18). An overview of the – not very satisfying – classification of the family, of which most species living in tropical regions, is given. Several nomenclatural changes are proposed: Uvarovitettix nodulosus (Fieber) is used as a replacement name for Mishtshenkotetrix brachyptera sensu Harz, Tettix brachyptera Lucas & Brisout being a synonym of Paratettix meridionalis, as a result of the designation by Harz of a juvenile of this species as lectotype of T. brachyptera. Tetrix austriaca Schmidt & Devkota is considered a synonym of Tetrix subulata. Tettix dohrnii Fieber is a brachypronotal specimen of Paratettix meridionalis, and a lectotype is designated. Tettix vittata Walker et Tettix subpustulatus Walker (lectotype designated) are considered to be synonyms of Paratettix histricus Stal, which is quite distinct from the South African species Paratettix scaber (Thunberg). A Dutch and a French identification key are provided as well as distribution maps. Data concerning the biology of the west palearctic Tetrigidae from the literature and from personal observations by the author are given. Tetrigidae are pioneering species, colonising wet localities with bare soil. The life cycle of all species seems to be similar, with a single reproduction period at the end of spring. However, T. undulata (and perhaps also T. bipunctata) can have a two-year life cycle, if the eggs are laid after teh 15th of July. The life cycle of T. tenuicornis and of the mediterranean species has not yet been elucidated. Tetrigidae are active primarily in the morning. They do not have individual territories and they feed with algues, bryophytes, but also with fallen leaves and humus. Data about seasonal migartions are contradictory.