9310600 Wheeler A phylogenetic analysis of the family Sepsidae (Insecta: Diptera) is proposed. The analysis will comprise three largely independent data sets consisting of egg, larval and adult morphological characters. The larval characters will be used to test the "ontogenetic criterion" for determining the polarity of character transformation series. Hennig's (1966) traditional version based on character precedence will be compared with Nelson's (1978) rule based on generality. The independent data set composed of egg and adult characters will be used to judge whether the ontogenetic criterion or outgroup comparison makes more accurate predictions about character polarity. Species ontogenies will be mapped onto the cladogram derived from egg and adult characters, allowing the direct study of changes in ontogeny over phylogenetic time, and the prevalence of widely discussed phenomena like insertions, substitutions, and deletions of states. A study of mating behavior and sperm competition in Sepsidae is under way at the University of Arizona; resulting characters will be mapped onto the cladogram in order to gain an understanding of why precopulatory guarding apparently evolved several times independently within the Sepsidae. %%% The Sepsidae are a family of flies with many of its members ovipositing and developing in cow dung as well as other decaying materials. This project will utilize independent data sets of egg, larval and adult characters to analyze relationships among all of the genera and about half of the species in the family. The resulting framework will be used to address the origins of interesting behaviors such a male guarding of females at the oviposition sites. ***
