Nine genera of phytoseiid mites with 22 species are described and illustrated on the basis of a survey of the literature, and by examination of material from orchards and their surroundings and of material from museum collections. Males, if available, are also described and figured. In addition to the species listed for the Netherlands, six species from around orchards in East Germany, Belgium and Poland were described briefly, and related species from other European countries (especially the British Isles and Germany) are noted. For each genus, a key to species (adult females) is given. For each species, a diagnosis is presented, and taxonomic problems are discussed for the following taxa: PhYloseius macropilis (Banks); Amblyseius reduclus Wainstein; A. cucumeris (Oudemans); A. masseei (Nesbitt); A. pOlentillae (Garman); A. rademacheri Dosse; A. isuki Chant. Keys are based on easily recognizable features and are aimed at "the interested non-taxonomist".