Molecular phylogenetic and chemical analyses, and morphological characterization of collections of North American Paraisaria specimens support the description of two new species and two new combinations for known species. P. cascadensis sp. nov. is a pathogen of Cyphoderris (Orthoptera) from the Pacific Northwest USA and P. pseudoheteropoda sp. nov. is a pathogen of cicadae (Hemiptera) from the Southeast USA. New combinations are made for Ophiocordyceps insignis and O. monticola based on morphological, ecological, and chemical study. A new cyclopeptide family proved indispensable in providing chemotaxonomic markers for resolving species in degraded herbarium specimens for which DNA sequencing is intractable. This approach enabled the critical linkage of a 142-year-old type specimen to a phylogenetic clade. The diversity of Paraisaria in North America and the utility of chemotaxonomy for the genus are discussed
