Geographical patterns of evolution in Neotropical Lepidoptera: differentiation of the species of Melinaea and Mechanitis (Nymphalidae,Ithomiinae)*

Abstract Biosystematic analysis incorporating abundant new field data from many parts of the Neotropics has led to an ordered revision of the mimetic ithomiine genera Melinaea and Mechanitis. The various polytypic species of these general probably served as prime movers for the differentiation of other mimetic butterflies in Quaternary forest refuges. The revisions are presented in the form of supplements to the works of Richard M. Fox on these genera, with analyses based on his divisions. Seven species (or monophyletic species-groups) and sixty-three well-differentiated geographic subspecies (six of these described here for the first time) are recognized in Melinaea. Specimens are illustrated which demonstrate intergradation between refuge-derived subspecies. Five species and fifty-two differentiated subspecies are recognized in Mechanitis, whose members are more abundant and gregarious, more plastic, and apparently more vagile than those of Melinaea, resulting in fewer clear-cut mimetic associations, more extensive blurring of differentiation patterns, and apparently fewer incipient biological species in this genus than in Melinaea.