We present a summary and analysis of the Diptera-related information published in Zootaxa from 2001 to 2020, with a focus on taxonomic papers. Altogether, 2,527 papers on Diptera were published, including 2,032 taxonomic papers and 1,931 papers containing new nomenclatural acts, equivalent to 22% of all publications with new nomenclatural acts for Diptera. The new nomenclatural acts include 7,431 new species, 277 new genera, 2,003 new synonymies, and 1,617 new combinations. A breakdown by family of new taxa and new replacement names proposed in the journal during the last two decades is provided, together with a comparison of Zootaxa’s output to that of all other taxonomic publications on Diptera. Our results show that the journal has contributed to 20% of all biodiversity discovery in this megadiverse insect order over the last 20 years, and to about 31% in the last decade.

Louse flies (Diptera, Hippoboscidae) are ectoparasites often found on birds. As they spend most of their life on their host, they are not often collected or studied. Hence, little is known about their species richness and prevalence on raptors in Canada. In this study, louse flies were collected from 184 out of 1467 raptors examined during the 2020 fall migration in southern Ontario, Canada, giving an overall prevalence of 12.5%. In total, 256 louse fly specimens were collected (mean intensity = 1.41) representing four species (identified morphologically, with support of DNA barcoding): Icosta americana (91.9%), Ornithomya anchineuria (0.3%), O. avicularia (7.3%) and O. bequaerti (0.3%). Mite clusters were found on 42% of O. avicularia. This study also presents the first North American record for O. avicularia and the presence of O. bequaerti in Europe was confirmed for the first time. Based on the different parameters recorded during banding, it appears that the host species and the month play a part in the presence of louse flies on the host. Further study of louse flies is needed to better understand their prevalence across different bird groups and geographic distribution.

Seven species of Calliphoridae are reported from the Galápagos Islands, Ecuador: Lucilia pionia (Walker), L. setosa (James), L. deceptor (Curran), L. eximia (Wiedemann), Cochliomyia macellaria (Fabricius), Chrysomya albiceps (Wiedemann), and Chrysomya megacephala (Fabricius). Lucilia eximia is newly recorded from the islands. Lucilia sp. near pionia is recorded from the island of Española. The distribution and collection records of these species are discussed and listed, and a key to their identification is provided. Chrysomya rufifacies (Macquart) is reported for the first time from mainland Ecuador and the identification of this species is outlined.

The Diptera fauna of the Galápagos Archipelago is updated and an annotated checklist is presented. Currently 50 families, 207 genera, and a minimum of 324 species are recorded from the islands. Approximately 107 species are considered to have arrived on the Galápagos Islands through human introductions, an estimated 101 species are considered endemic, 42 species have naturally colonized the islands from mainland Americas, 21 species are either introduced or arrived naturally and 53 species remain unidentified. The following new combination is proposed: Chrysanthrax primitivus (Walker) is moved to Hemipenthes Loew as H. primitivus (Walker) comb. nov. All references to the Galápagos taxonomic literature are included, known island species distributions listed and general remarks on the biology of many species are provided.

The Nearctic species of the brachystomatid genus Heleodromia Haliday are revised. The following six species are recognized: Heleodromia boreoalpina Saigusa, H. chillcotti Sinclair sp. nov., H. cranehollowensis Cumming and Coovert sp. nov., H. irwini Wagner, H. pullata (Melander), and H. woodi Brooks sp. nov. The following new Palearctic distribution records are also reported: H. boreoalpina (Russian Far East), H. irwini (Germany, Russian Far East), and H. immaculata Haliday (Russian Far East). A key to adults, illustrations of male terminalia, and known distributions are included. Les espèces néarctiques du genre de brachystomatidés Heleodromia Haliday sont révisées. Les six espèces suivantes sont reconnues: Heleodromia boreoalpina Saigusa, H. chillcotti Sinclair sp. nov., H. cranehollowensis Cumming et Coovert sp. nov., H. irwini Wagner, H. pullata (Melander) et H. woodi Brooks sp. nov. On annonce aussi les nouvelles occurrences suivantes dans la distribution paléarctique: H. boreoalpina (extrême orient russe), H. irwini (Allemagne, extrême orient russe) et H. immaculata Haliday (extrême orient russe). Une clé des adultes, des illustrations des organes terminaux des mâles et les distributions connues sont incluses.