Abstract
Examination of Baltic amber Plecoptera reveals a new species of Isoperla namely: Isoperla baltica sp. nov. The placement of this new species is supported by an in-depth comparison of apomorphies supporting families, subfamilies, and suborders. Contrary to previous descriptions of many fossil species, we took advantage of the good preservation of the genitalia to describe and compare this new species to its extant congeners. Finally, we discuss the usefulness and limitations of relying on wing venation to identify diagnostic characters in Plecoptera a new specimen ofPteroliriope sinitshenkovae Cui, Béthoux, Kondratieff, Shih & Ren, 2016 with numerous crossveinsand an original organization of forewing veins.