The final volume of this 4-volume monograph on the Agromyzidae of Hungary. Volume 4 contains the third systematic part of the subfamily Phytomyzinae with the genera Chromatomyia (33 species), Napomyza (19 species), Phytomyza (166 species) for a total of 228 species. A Catalogue with occurrence data in Hungary, in the Czech Republic and in Slovakia is also given. Additions and corrections to Volumes 1-3 are given. Eighteen new species for science are described. The text is closed by a Diptera and plant name index. The volume is richly illustrated by more than 2300 – mostly original – figures arranged in 226 figure plates.