North American Tanytarsus I. Descriptions and Keys to Species in the Eminulus, Gregarius, Lugens and mendax Species Groups (Diptera: Chironomidae)

Adult males, pupae and larvae of Tanytarsus acifer sp.n., T. aigos sp.n., T. angulatus Kawai, T. bathophilus Kieffer, T. becki sp.n., T. boltoni sp.n., T. challeti Spies, T. confusus Malloch, T. dendyi Sublette, T. epleri sp.n., T. gibbus sp.n., T. guerlus Roback, T. harperi sp.n., T. lestagei Goetghebuer, T. martini sp.n., T. mendax Kieffer, T. messersmithi sp.n., T. nearcticus Butler, T. neoflavellus Malloch, T. occultus Brundin, T. pelsuei Spies, T. sepp sp.n., T. volgensis Miseiko and T. wirthi sp.n., and adult males and pupae of Tanytarsus bayi sp.n., T. dispar Lindeberg, T. gracilentus Holmgren, T. gregarius Kieffer, T. inaequalis Goetghebuer, and T. lobiger sp.n. as well as adult males of Tanytarsus appendiculatus sp.n., T. chloris sp.n., T. herrmanni sp.n., and T. pathudsoni sp.n. are diagnosed and described. T. islandicus Malloch is a new junior synonym of T. lestagei. Paratanytarsus fatigans Johannsen comb. n. and Paratanytarsus varela Roback comb. n. were previously placed in Tanytarsus . Provided under each species is a list of new synonymies, and references to previous reviews. Keys to all stages of the included species are presented as well as comments on their distribution. Most of the adult males examined fit well in the European species groups, but a phylogenetic analysis needs to be conducted to see if these groups hold for the immature stages.