The mosquitoes and chaoborids of Glacier and Yellowstone National Parks with new records and Ochlerotatus nevadensis, a new state record for Montana.

The known mosquito fauna of Glacier National Park, Montana, and Yellowstone National Park, Wyoming, is reported with new records, including a list of the species of Chaoboridae known from both parks. Ochlerotatus nevadensis (= Aedes nevadensis) from Glacier National Park is a new record for the state of Montana.