Six new flower fly species are described: Blera chillcotti Thompson (Nepal), Sphiximorpha mcalpinei Thompson (Mexico), Psilota shewelli Thompson (Nepal), Rhopalosyrphus teskeyi Thompson (Argentina), Parasyrphus vockerothi Thompson (United States of America and Canada), and Lycopale woodi Thompson (Mexico). Keys are provided to the species of the genera Lycopale Hull and Rhopalosyrphus Giglio-Tos, the Nearctic species of Sphiximorpha Rondani, and the Oriental species of Blera Billberg and Psilota Meigen.

Pareuthychaeta Hennig was previously known only from two described species in Eocene Baltic amber (Lutetian, ca. 42 Ma), Pareuthychaeta electrica Hennig and Pareuthychaeta minuta (Meunier), some details of which are revised based on new specimens. A third Baltic species is described, Pareuthychaeta mcalpinei Grimaldi, sp. nov. Another species, Pareuthychaeta eoindica Grimaldi, sp. nov., is described in earliest Eocene (Ypresian-aged, ca. 50–52 Ma) amber from Gujarat, western India. Comments are provided on the relationships of Pareuthychaeta to Recent genera of Diastatidae sensu lato (including Campichoetinae), and implications of this extinct genus are discussed regarding biogeography and the early Paleogene Schizophora radiations.

A survey of muscid flies from Churchill, Manitoba, Canada, in 2007 yielded 155 species. Some components of species richness and composition of this contemporary assemblage were compared with those of a historical (pre-1965) assemblage, and the contribution of the three collecting methods used in the 2007 survey protocol was evaluated. Estimates of species richness indicated that Malaise traps yielded more species than did pan traps or sweep netting, and that species composition did not differ significantly between Malaise trap and pan trap catches. These results suggest that Malaise traps and sweep netting are adequate methods to survey northern Muscidae. We report little difference in estimated species richness and composition between time periods for material collected by sweep netting. When all material from the 2007 survey was pooled, 87% of the pre-1965 species were collected again in 2007. Most nonoverlapping species between time periods were rare in samples and (or) collected by different methods, suggesting a failure to detect as the most likely explanation for their absence in one assemblage. Nevertheless, the proportion of aquatic and semiaquatic species of Spilogona Schnabl was more than twice as high in the list of species not recovered in 2007 than in the pre-1965 assemblage.

Pinacocerus Van Duzee and Yumbera Bickel are reviewed. Pinacocerus is found in Chile and Argentina and comprises two species, Pinacocerus nodicornis Van Duzee and Pinacocerus candiptorumsp. nov. from Chile. Yumbera comprises six species, five from eastern mainland Australia and Yumbera trisignatasp. nov. from Tasmania. The two genera show remarkable parallel evolution in modification of the male antenna.

Dolichocephala Macquart is revised for America, north of Mexico. New descriptions and diagnoses of the genus and a previously known species are presented. Six new species are described: Dolichocephala arnaudisp. nov., Dolichocephala borkentisp. nov., Dolichocephala chillcottisp. nov., Dolichocephala teskeyisp. nov., Dolichocephala vockerothisp. nov., and Dolichocephala woodisp. nov. Previous Nearctic records of Dolichocephala irrorata Fallén are based on misidentifications. Dolichocephala bellstedti Joost is newly recorded from Sweden. A key to adults, photographs of wings, illustrations of male terminalia, and known distributions are included.

The shore-fly genus Oedenopiforma Cogan is reviewed, including new information on Oedenopiforma argentea (distribution), Oedenopiforma javana (comb. nov. and O. orientalissyn. nov.), and Oedenopiforma vockerothi (sp. nov. from United Arab Emirates). Structures of the male terminalia of these three species, a diagnosis of the genus, and a key to the included genera of Dryxini and species of Oedenopiforma are presented.

The cave-living and monobasic fungus gnat genus Speolepta Edwards is reviewed with a description of the first Nearctic species, Speolepta vockerothisp. nov., from Canada (caves in Ontario and British Columbia) and the United States (Alaska). Its morphology, life history, and biology are documented and compared with the single European species Speolepta leptogaster (Winnertz). A further new species, Speolepta orientalissp.nov., is described based on a single male from northern Vietnam, representing the first record of this genus from the Oriental Region.

The Microphorella chillcotti species group is established for two new species from western North America: Microphorella chillcottisp. nov. and Microphorella vockerothisp. nov. The relationships of this lineage to the remainder of the Microphorella group of genera are discussed.

Nine species of Icteromyza Hendel, a subgenus of Cerodontha Rondani, were previously known in the Nearctic: Cerodontha (Icteromyza) atrissima Spencer, Cerodontha (Icteromyza) capitata (Zetterstedt), Cerodontha (Icteromyza) churchillensis Spencer, Cerodontha (Icteromyza) fuscifrons Spencer, Cerodontha (Icteromyza) lineella (Zetterstedt), Cerodontha (Icteromyza) longipennis (Loew), Cerodontha (Icteromyza) montanoides Spencer, Cerodontha (Icteromyza) pilosa Boucher, and Cerodontha (Icteromyza) temeculensis Spencer. Three new species are here described for this region: Cerodontha (Icteromyza) griffonensissp. nov.; Cerodontha (Icteromyza) vockerothisp. nov.; Cerodontha (Icteromyza) woodisp. nov. Species descriptions and illustrations, additional notes, and a new identification key for the Nearctic species of Cerodontha (Icteromyza) are provided.

Anastrepha woodisp. nov. is described and illustrated based on specimens from Colombia, Costa Rica, and Panama. Anastrepha loewi Stone, the species most similar to A. woodi, is redescribed, and the two species are compared.

The nominal taxon Tachina macularis Wiedemann is revised and redescribed from the adult and first instar larva. It is transferred from its current status as a valid species of Protomiltogramma Townsend to a position as a valid species of Eremasiomyia Rohdendorf, comb. nov. and senior synonym of Setulia luteicornis Villeneuve, syn. nov., Eremasiomyia setulioides Rohdendorf, syn. nov., and Eremasiomyia orientalis Verves, syn. nov. The nominal species Sphecapatodes maroccana Séguy is revised and redescribed from the adult, and is shown to belong to Miltogramma Meigen, comb. nov. The nominal genus-group taxon Capnopteron Rohdendorf was originally proposed as a subgenus of Miltogramma with the type species Miltogramma maculigerum Speiser sensu Rohdendorf). However, the latter is shown to be a misidentification of Miltogramma maroccana (Séguy), which herewith is fixed as the type species of Capnopteron.

The synonymy of Prionocera chosenicola Alexander with Prionocera tjederi Mannheims is discussed and the following syn. nov. is proposed: Prionocera mannheimsi Savchenko = Prionocera byersi Brodo. Prionocera parrii (Kirby) remains a nomen dubium. Significant range extensions are noted for Prionocera dimidiata (Loew), Prionocera ominosa (Alexander), Prionocera oregonica Alexander, Prionocera pubescens Loew, Prionocera ringdahli Tjeder, Prionocera serricornis (Zetterstedt), Prionocera subserricornis (Zetterstedt), and Prionocera turcica (Fabricius).

Larvae, pupae, and adult males and females of Clytocerus (Boreoclytocerus) americanus (Kincaid), as well as adult males and females of Clytocerus (Boreoclytocerus) microlimnetessp. nov. were collected during various biodiversity surveys in the southeastern United States. Clytocerus (B.) americanus is redescribed, C. (B.) microlimnetes is described, and the natural history and relationships of Nearctic species of Clytocerus are discussed.