Because this species of katydid is flightless, the founding individuals of the two westmost populations are likely to have been from one or both well-established colonies to the east (and not from Europe).
Acknowledgement: This SINA species had escaped the notice of SINA’s editor for 19 years until Brandon Woo called the editor’s attention to it. At that time, Woo was an undergraduate at Cornell and an avid searcher and audio recorder of singing insects in the field, and he had extended his searches to BugGuide and iNaturalist where photographers and naturalists were posting their photographs of insects in hope of getting their insects identified by specialists (such as Woo). TJW (March 2019)