Our knowledge of the phylogenetic relationships of Diptera advanced through the 20th century at an unprecedented rate; the two crowning achievements of the century were Hennig's magnum opus – the Handbuch der Zoologie treatment of the order and Volume 3 of the Manual of Nearctic Diptera series, edited by McAlpine and Wood. The Manual is outstanding because of its scope and rigorous, consistent approach, treating the relationships of the entire order at family level using Hennigian argumentation. Synapomorphic characters from all life stages were identified using outgroup comparison and monophyletic taxa were established using synapomorphies mapped onto nodes. The Manual chapters energized a generation of students to publish rigorous, quantitative cladistic phylogenetic treatments of many dipteran groups. The chapters also acted as an authoritative scaffold for the development of dipteran molecular systematics in the 1990s. No other megadiverse insect order has had such an influential phylogenetic springboard into the 21st century.

Euthera Loew is a small but cosmopolitan genus of Tachinidae with distinctive smoky black cross bands on the wings. There are three described species in North America, Euthera bicolor Coquillett, Euthera setifacies Brooks, and Euthera tentatrix Loew. A new species from California and New Mexico is described as Euthera woodisp. nov. in honour of dipterist D. Monty Wood. A key and digital images are provided for the identification of the four species, and the three previously described species are diagnosed. Oebalus mexicana (Sailer) and Nezara viridula (L.) (Heteroptera: Pentatomidae) are new host records for E. bicolor and E. tentatrix, respectively.

The 19 New World species of Sericomyia Meigen are reviewed, including one species new to North America (Sericomyia jakutica (Stackelberg)) and one previously undescribed species (Sericomyia vockerothi Skevington sp. nov. from Alberta, Minnesota, Northwest Territories, Quebec, and Yukon Territory). Mallota powelli Nayar and Cole is recognized as a junior synonym of Sericomyia flagrans (Osten Sacken). A description and illustrations of S. vockerothi and an illustrated key to New World Sericomyia are presented. DNA barcode data are presented for 14 New World species and a cytochrome oxidase subunit I gene tree is presented and discussed. Genetic evidence supports the contention that the subgenera of Sericomyia are not monophyletic. Arctophila Schiner and Conosyprhus Frey are thus proposed as junior synonyms of Sericomyia.

We describe three new species of fruit flies (Tephritidae: Tephritinae) (Gymnocarena defoeisp. nov. and Gymnocarenanorrbomisp. nov., from eastern North America and Gymnocarena monzonisp. nov. from Guatemala) and redescribe Gymnocarena mississippiensis Norrbom. Gymnocarena monzoni is the first Gymnocarena species to be recorded from Guatemala. This brings the total number of named species in this genus to 19. New larval host plant (Asteraceae) records for Gymnocarena include Verbesina helianthoides Michx. for G. mississippiensis and G. norrbomi, Verbesinaalternifolia (L.) Britton ex Kearney for G. norrbomi, and Viguiera cordata (Hook. and Arn.) D'Arcy for G. monzoni. The latter represents the first record for Gymnocarena in Viguiera Kunth. Gymnocarena larvae were also recorded from Verbesina virginica L. but not identified to species. A revised key to the known species of Gymnocarena and additional information on larval host plants and biology are provided.

The male genital tract of Axymyiidae and Tanyderidae, represented by Axymyia furcata McAtee and Protoplasa fitchii Osten Sacken, respectively, are described and illustrated for the first time. The tract of A. furcata is foreshortened, with relatively short, thick vasa deferentia that meet medially at the ejaculatory duct, which empties dorsal to the ejaculatory apodeme. The accessory glands are large and either firmly appressed or fused medially. The tract of P. fitchii has elongate vasa deferentia that curve ventrally and enter the ejaculatory duct separately. The short accessory glands are separate but their exit is uncertain. Neither of these male genital tracts shed further light on the phylogenetic position of these families within the nematocerous Diptera, although Tanyderidae do lack the synapomorphic multi-chambered accessory glands grouping Ptychopteridae + Culicomorpha + Bibionomorpha.

The morphology of all life stages of the semi-aquatic nematocerous fly, Axymyia furcata McAtee (Diptera: Axymyiidae), is documented, with emphasis on use of scanning electron microscopy (SEM). Our data on some life stages (e.g., egg, first-instar larvae) represent the first SEM examination of these stages in axymyiids. Among the unexpected results is absence of an egg burster in first instars. Most characters provided little evidence of a phylogenetic relationship with any other clade of nematocerous Diptera, reflecting a need for comprehensive morphological studies of the immatures of many families.

Vockerothempissubgen. nov., a new subgenus of Rhamphomyia, is described and includes the following species: Rhamphomyia (Vockerothempis) arakawae Matsumura, Rhamphomyia (Vockerothempis) calcarifera Saigusa, and Rhamphomyia (Vockerothempis) japonica Frey from Japan, and Rhamphomyia (Vockerothempis) umbrosa Loew, Rhamphomyia (Vockerothempis) brevisetosasp. nov., Rhamphomyia (Vockerothempis) chillcottianasp. nov., and Rhamphomyia (Vockerothempis) fortisetosasp. nov. from North America. Zoogeography, phylogenetic relationships within Vockerothempis and subgeneric classification of Rhamphomyia are discussed.

Rapid and recent lineage radiations pose challenges to systematists. Using members of the highly diverse Simulium arcticum Malloch complex, we tested whether the cytochrome c oxidase subunit I (COI) barcoding gene can differentiate black fly sibling species. Members of the S. arcticum complex were monophyletic in relation to two morphospecies and two cryptic species of the Simulium malyschevi Dorogostaisky et al. and Simulium noelleri Friederichs species-groups, respectively. Of five S. arcticum sibling species analysed, only Simulium negativum Adler et al. was monophyletic. No other members of the complex could be distinguished using COI barcodes. The inability to resolve S. arcticum sibling species resulted because (1) haplotypes were shared between species and (2) the distribution of interspecific genetic distances completely overlapped the range of variation within species. Potential sources of incongruence between barcode data and species boundaries include imperfect taxonomy, inadequate genetic information, incomplete lineage sorting, and/or introgressive hybridization. We ruled out imperfect taxonomy because chromosomal, ecological, and distributional evidence support the validity of S. arcticum sibling species. Therefore, current nomenclature should be maintained pending further study. We conclude that one or more of the latter three sources of incongruence could be responsible for the lack of reciprocal monophyly among species of the S. arcticum complex.

The sympycnine genus Telmaturgus Mik is reviewed for the Nearctic region, and includes three species: Telmaturgus parvus (Van Duzee), Telmaturgus robinsonisp. nov., and Telmaturgus vockerothisp. nov. Species of Telmaturgus can be recognized by the reduced number of dorsocentral setae (three pairs in Nearctic species) and the projecting lower face of females. Examination of the holotype of T. parvus reveals that the widespread species previously thought to be T. parvus is T. robinsoni. A key to species and comments on the taxonomic history and ecology of the genus are provided.

Helina richardisp. nov. is described from Morocco and Spain. The presence of setulae at the base of vein R4+5 suggests placement in Mydaea Robineau-Desvoidy but other characters and the structure of the female ovipositor indicate that it is otherwise a typical species of Helina Robineau-Desvoidy.

This study examines the seven described species of Epiphragma Osten Sacken (Diptera: Tipulidae s.l.) known to occur in North America including Mexico. A key to species, descriptions, distributional ranges, habitat information, and literature references are given and the wing patterning and male genitalia are illustrated. The male of Epiphragma celator Alexander is described for the first time and the species range is extended north from Michoacan, Mexico to southern Arizona, United States of America. The range of Epiphragma arizonense Alexander is extended from southern Arizona south to Sinaloa, Mexico. The male hypopygium of Epiphragma nebulosum (Bellardi) and wing and hypopygium of Epiphragmaoreonympha Alexander are illustrated for the first time.