Cuerna striata

This is a complex of many closely-related and variable species with their limits poorly defined. The most recent revision collapsed the complex back into one species until further study can be used to determine the limits of the species. C. striata is interpreted here sensu Nielson, i.e. as a variable species complex widely distributed in the northern parts of the continent. Populations from geographically distant localities can be as different as good species, yet dividing geographical variants into discrete taxa is difficult. Nielson pointed out that specimens from the western parts of the United States, Canada, and Alaska are smaller and display relatively longer caudal and shorter lateral processes of the male aedeagus, and female sternum VIII with lateral plates connected by a more narrow bridge than specimens from the eastern parts of the United States and Canada. Hamilton interpreted the eastern forms as C. striata and C. lugens (endemic to Nova Scotia, synonymized by Nielson with C. striata ). He interpreted the western forms as C. septentrionalis (originally described from Northwest Territories and also synonymized by Nielson with C. striata ) and five newly described species, four of them found only in Canada. Examination of specimens from the entire range of the striata complex suggests that C. inflata , C. lugens , C. nielsoni , C. pseudoalba , and C. reducta represent within-population variants, whereas cuesta seems to have a well-defined range in the northwestern United States and British Columbia and may merit subspecific status. Several additional forms from Arizona, Nevada, and Utah, interpreted here as C. striata s. l., appear to be distinct and may be recognized as separate species in the future, when the entire striata species group is better studied.