Historical-species
Guides
Melanoplus spretus
Rocky Mountain Locust
Melanoplus spretus, the Rocky Mountain Locust, was a species of locust that ranged through the western United States and parts of Canada until the late 19th century. It was one of the most destructive agricultural pests in North American history, forming swarms of unprecedented size—one 1875 swarm was estimated at 198,000 square miles. The species is now extinct, last observed in the early 1900s. It is considered by some authorities to represent a gregarious, migratory phase of Melanoplus sanguinipes rather than a distinct species.