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.
Distribution in South Africa. Hoverflies can be found all over the country between the sea-shores and the mountains. In total, there are at least 180 species recorded from South Africa. The number of species declines from the northeast to the southwest. However, some species have only or predominately been found in the Western Cape.
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.