Taxonomic Uncertainty, the Biological Species Concept and the Nearctic Butterflies: a Reappraisal after Twenty Years

Abstract

In 1961 Paul Ehrlich surveyed the Nearctic butterfly fauna in order to demonstrate that the biological species concept had "outlived its usefulness." A reappraisal of two genera, Lethe and Piens (sens. [at) , after twenty years leads to the conclusion that the biological species concept is still very useful in both systematics and evolutionary biology.