The Pepsis menechma Lepeletier (Hymenoptera: Pompilidae: Pepsinae) taxonomic and nomenclatural problem

Abstract

Hurd (1952), in revising the Nearctic species of Pepsis Fabricius, separated P. cerberus Lucas from P. elegans Lepeletier based on external morphology and geography. Vardy (2005), in his Western Hemisphere Pepsis revision, combined these taxa and several Neotropical color and structural variants in a broad definition of P. menechma Lepeletier extending across ~11,250 km and two continents. Vardy (2005) synonymized the familiar and well-documented, 160-year-old P. elegans under P. menechma probably because it appeared several pages later in Lepeletier’s (1845) Histoire Naturelle des Insectes. Hyménoptères . Vardy’s (2005) interpretation of Pepsis menechma as a viable species presents a taxonomic and nomenclatural problem. He violated the principle of nomenclatural stability in synonymizing the widely and established species names P. elegans and P. cerberus under P. menechma, a name that had not been used for 160 years. Recent discoveries warrant a re-evaluation of the problematic taxonomy of this species complex. Morphological and ecological divergence of P. elegans and its sister taxon, P. cerberus, combined with their narrow sympatric distribution justifies species recognition. Hurd’s (1952) two species concept for P. elegans and P. cerberus is more practicable, useful, and nomenclaturally acceptable than Vardy’s (2005) P. menechma. Pepsis cerberus Lucas and P. elegans Lepeletier should be reinstated as species and removed from the synonymy of Pepsis menechma Lepeletier.