The Nemourinae (Insecta, Nemouridae) of the eastern Nearctic Author Grubbs, Scott A. 0000-0003-2170-9716 Department of Biology and Center for Biodiversity Studies, Western Kentucky University, Bowling Green, Kentucky, 42101, USA Department of Biology and Monte L. Bean Life Science Museum, Brigham Young University, Provo, Utah, 84602, USA & scott. grubbs @ wku. edu; https: // orcid. org / 0000 - 0003 - 2170 - 9716 scott.grubbs@wku.edu Author Baumann, Richard W. 0000-0003-0838-4080 richard _ baumann @ byu. edu; https: // orcid. org / 0000 - 0003 - 0838 - 4080 richard_baumann@byu.edu text Zootaxa 2023 2023-06-19 5306 1 1 53 http://dx.doi.org/10.11646/zootaxa.5306.1.1 journal article 56121 10.11646/zootaxa.5306.1.1 a81c4131-079c-4d9f-8333-70c0de3fb44e 1175-5326 8054287 21AD4F85-E313-47CB-BA98-9896D2B1DC05 VI . Genus Prostoia Ricker, 1952 http://lsid.speciesfile.org/urn:lsid: Plecoptera .speciesfile.org:TaxonName:6092 Type species. Nemoura completa Walker, 1852 Range. Nearctic ( DeWalt et al. 2022 ). Diagnosis. See Baumann (1975) for a comprehensive description of the genus and Grubbs et al. (2014) for an SEM-based treatment for all five species. Species key to eastern Nearctic Prostoia adult males and females (modified from Grubbs et al. 2014 ) 1 Males .............................................................................................. 2 - Females............................................................................................. 5 2 Dorsal sclerite with secondarily reduced lateral arms ( Fig. 79 ); ventral sclerite bears an ornate, secondarily divided process apically ( Figs. 70, 72‒73 )......................................................................... P. hallasi - Dorsal sclerite possesses lateral arms ( Figs. 66 , 82 , 88 ); apex of ventral sclerite simple, not divided apically ( Figs. 61 , 77 , 85 ) ................................................................................................... 3 3 Lateral arms longer and sinuous, reaching nearly to ½ the length of the ventral sclerite ( Figs. 85‒87 )............. P. similis - Lateral arms shorter, extending <¼ the length of the ventral sclerite ( Figs. 66 , 82 ).................................. 4 4 In dorsal view, ventral sclerite parallel-sided in basal ⅓ ( Fig. 61 ); lateral arms sickle-shaped, gradually recurved ( Figs. 66‒67 )........................................................................................... P. completa - In dorsal view, ventral sclerite gradually widening in basal ⅓ ( Fig. 77 ); lateral arms somewhat triangular in shape, tips flared laterally ( Figs. 74 , 82‒83 ).................................................................... P. ozarkensis 5 7 th and 8 th abdominal sterna not fused medially ( Fig. 75‒76 ), with a well-developed subgenital plate that is convex, extending over the anteromedial margin of the 9 th sternum and slightly notched medially ( Figs. 75‒76 ).................... P. hallasi - 7 th and 8 th abdominal sterna fused medially, subgenital plate not convex and bearing a distinct medial notch or not ( Figs. 68 , 84 , 93‒94 ).............................................................................................. 6 6 Posterior margin of 8 th sternum with a distinct medial notch, lateral lobes of subgenital plate distinctly angular, projecting ca. 1/4 over anterior margin of 9 th sternum ( Figs. 93‒94 ).................................................. P. similis - Posterior margin of 8 th sternum with a shallow medial notch, lateral lobes scarcely projecting posteriorly ( Figs. 68 , 84 ).................................................................................. P. completa and P. ozarkensis