The state's most important rivers are the Missouri, rising in southwest Montana and flowing north and then east across the state, and the Yellowstone, which crosses southeastern Montana to join the Missouri in North Dakota near the Montana border.
Habitats. Hoverflies can be found in every biotope but not in deserts. Each species tends to prefer a certain type of habitat and is limited to a distinct range within the country. There are relatively few species with broad habitat tolerances that enable them to be distributed throughout southern Africa.
Cluster flies are capable of crawling through small openings in the walls of a structure. They hibernate in secluded parts of houses like attics and wall voids. On sunny winter days, the wall voids become warm and the cluster flies try to move toward light. Very often they find themselves in the inhabited parts of the house and the move to the windows. They cluster around the windows and they leave stains on walls and curtains if crushed. The cluster fly life cycle begins when a female lays her eggs in the soil in late summer or early fall.