The systematic position of the Piophilidae sens. lat. within a group of nine schizophorous families with tephritid-like ovipositors (Lonchaeidae, Otitidae, Platystomatidae, Pyrgotidae, Tephritidae, Tachiniscidae, Richardiidae, Pallopteridae, and Piophilidae) is elucidated. It is shown to be a sister-group of the Pallopteridae, and these two families together with the Richardiidae comprise a monophyletic suprafamily unit within the larger group of families. The evolutionary changes that occurred within the Piophilidae are analyzed and the supposed phylogeny of its component taxa is portrayed. The family is redefined to include neottiophilids and thyreophorids and is classified into two subfamilies, Neottiophilinae and Piophilinae; the latter is divided into two tribes, Mycetaulini and Piophilini (with subtribes Piophilina and Thyreophorina). Twenty-three genera are recognized and taxonomically defined; this includes description of two new genera, Neopiophila and Parapiophila. Clusina Curran is synonymized with Protopiophila Duda (new synonymy), and four nominal species are placed in synonymy for the first time, i.e. Piophila anomala Malloch and Piophila serosa Melander and Spuler = Parapiophila vulgaris (Fallén) (new synonymy), Piophila flavifacies Brunetti = P. casei (Linnaeus) (new synonymy), and Mycetaulus pulchellus Banks = Mycetaulus longipennis Loew (new synonymy). Six new species, Actenoptera avalona (Newfoundland), Neopiophila setaluna (Northwest Territories), Protopiophila arrichosa (Peru and British Honduras), Protopiophila pallida (Peru and British Guiana), Prochyliza azteca (Mexico), and Prochyliza inca (Peru) are described. The following 20 new combinations are made: Mycetaulus lituratus (Melander and Spuler), Allopiophila testacea (Melander), Protopiophila nigriventris (Curran), Prochyliza lundbecki (Duda), nigricornis (Meigen), nigricoxa (Melander and Spuler) and nigrimana (Meigen), Arctopiophila arctica (Holmgren), Parapiophila atrifrons (Melander and Spuler), calceata (Duda), coerulescens (Zetterstedt), dudai (Frey), flavipes (Holmgren), lonchaeoides (Zetterstedt), nitidissima (Melander and Spuler), pectiniventris (Duda), penicillata (Steyskal), vulgaris (Fallén), and xanthopoda (Melander and Spuler). In all, 67 valid species are placed, their geographic distributions are outlined, and the zoogeographic implications are discussed. A lectotype is designated for Piophila flavitarsis Meigen = Madiza glabra Fallén (Milichiidae).
A key to subfamilies, tribes, and genera is provided, and keys to world species are given where needed. An annotated world list of all names referred to the family (sens. lat.) is provided. The paper includes 58 figures, two tables, and 122 literature references.