ABSTRACT
Character states for the tribe, genus, and species of the genus Leptinotarsa have been selected for the analysis of the classification of the group. The Groundplan Divergence (GPD) method, as discussed by W. H. Wagner, seeks to find the simplest phylogenetic explanation of comparative data. It is concerned with amounts, directions, and sequences of the radiating patterns of genetic divergence. These are estimated on the basis of correlations of character states. Branching sequences and ancestor-descendant relationships are most important in GPD methods. The more parsimonious and compatible the character correlations are, the more probable the resulting phylogenetic tree. The generic characters are limited to external morphological features of adults, including the male genitalia. These characters are: open procoxal cavities and simple claws. Additional characters useful in delimiting genera include apical segment of maxillary palpi and mesosternum flat. Among the most significant external characters are surface punctations and various elytra markings, including vittae.
