COLORADO MAYFLIES (EPHEMEROPTERA) - AN ANNOTATED INVENTORY

Fourteen families, 41 genera, and 97 species of Ephemeroptera are conf irmed for the state of Colorado. Of these, two families, 11 genera (Ac erpenna, Apobaetis, Barbaetis, Camelobaetidius, Centroptilum, Heterocl oeon, Ironopsis, Lachlania, Macdunnoa, Neochoroterpes, and Pseudiron), and 37 species are reported for the first time. The probability of ce rtain additional genera eventually being found in Colorado is discusse d. Previous and new records from 48 of the 63 Colorado counties are pr ovided. The eastern plains region of the state remains relatively poor ly known. Colorado species fit one of the following distributional pat terns: continental widespread, continental mountain, northern transcon tinental, northwestern, Rocky Mountain, southwestern, eastern-midweste rn fringe, or western sand/silt riverine. Taxonomic, distributional, a nd other data that may be pertinent to Colorado Ephemeroptera are give n for each species.