An estimated two million species are known to science, with nearly half of these being insects. Although these numbers may seem impressive, they represent a small fraction of the diversity thought to exist. Because the vast majority of species remain undiscovered and unnamed, there is an acute need for revisionary studies. Megadiverse taxa such as the Diptera are especially problematic because of the shortage of practicing systematists. One of the goals of my laboratory is to conduct revisionary studies of various insect taxa, concentrating on aquatic Diptera and other aquatic insects. Most of this research is aimed at describing and naming the diversity of these taxa and elucidating their phylogenetic relationships. Projects in my laboratory have focused on several families of lower (aka nematocerous) Diptera, including Blephariceridae, Deuterophlebiidae, Nymphomyiidae, Psychodidae, Simuliidae, and Tipuloidea. Related investigations include aspects of the morphology, biogeography, and historical ecology of aquatic insects, morphological and ecological adaptations of insects in unusual aquatic habitats (especially torrential streams and hyporheic [subterranean] habitats), and phylogenetic congruence of different character data (e.g., larval, adult, chromosomal, molecular, ecological).