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.
Mayflies also known as shadflies or fishflies in Canada, are aquatic insects belonging to the order Ephemeroptera. This order is part of an ancient group of insects termed the Palaeoptera, which also contains dragonflies and damselflies. Over 3,000 species of mayfly are known worldwide, grouped into over 400 genera in 42 families. Mayflies are relatively primitive insects and exhibit a number of ancestral traits that were probably present in the first flying insects, such as long tails and wings that do not fold flat over the abdomen.