Both sexes of Achalcus bicolor sp.n., Achalcus longicercus sp.n., and Australachalcus latipennis sp.n. are described as additions to the Nearctic achalcine fauna. Diagnoses of five unnamed Achalcus species represented only by females are given. A key to Nearctic males and females including 10 unnamed species is provided. The new Achalcus records considerably extend the known distribution of the genus in North America, especially in the central and eastern states. Australachalcus latipennis sp.n. is the first known Nearctic species of this predominantly Neotropical and New Zealand genus. Achalcus bicolor sp.n. from Montana, Manitoba and Ontario clearly belongs to the Achalcus flavicollis species group. The eastern Achalcus longicercus sp.n. is not included in the latter species group due to the lack of a dorsal bristle on tibia I and the absence of a preapical anterodorsal bristle on femur III in both sexes. It features postgonites with strong hook-like apical processes possibly unique to this species. The presence and number of dorsal bristles on tibia I seem to be of both diagnostic and phylogenetic relevance. All northern achalcine species were collected between June and September, whereas some Californian species were taken in May and Australachalcus latipennis sp.n. from Arizona in October - November.
Quametopia gen. n. is established on the basis of recent phylogenetic analysis of taxa formerly assembled under the genus Mumetopia Melander, 1913 to include M. terminalis (Loew, 1863) and two new closely related Nearctic species of Anthomyzidae. The new genus is diagnosed and its phylogenetic relationships discussed. Quametopia terminalis (Loew, 1863) comb. n. is transferred from Mumetopia and redescribed based on revision of the type material (lectotypes of Anthophilina terminalis Loew, 1863 and its synonym Mumetopia nitens Melander, 1913 are designated) and other extensive material. Quametopia clintonia sp. n. and Q. amplistylus sp. n. (both from Canada, USA) are described and relationships of all three Quametopia species discussed. Immature stages of Q. terminalis and Q. clintonia sp. n. obtained by means of adult-to-adult rearing are described (1st- and 2nd-instar larvae for the first time in the family Anthomyzidae) and illustrated. Keys to adults, eggs, larvae and puparia of Quametopia species are presented. Biology (habitat and host-plant associations, life history) of Q. terminalis and Q. clintonia sp. n. are studied in detail and their ecological separation demonstrated. Distribution of all Quametopia species is reviewed. and Jindřich Roháček, Kevin N. Barber.