Show destructive locusts locust when agriculture to be established generally in the lie great plains region of the united states lying west of the mississippi river and east of the rocky thoun mountains agns during the decade 1870 1670 80 ff migratory species of grasshopper commonly ionn known as the rocky mountain locust frequently swooped down from its breeding grounds on the benches of tile the mountain range in such great swarms as to destroy practically all cultivated crops over vast areas of country reducing thousands of families almost to starvation |