http://en.wikipedia.org/wiki/Rocky_Mountain_locust
Anyone reading the Little House on the Prairie series will probably remember the locust incident with particular vividity. In On the Banks of Plum Creek, the family’s homestead is ravaged by a cloud of locusts that arrive in such numbers they blocked out the sun. I’d been wondering why such invasions no longer make the news (though Paris Hilton and co. are a similar plague), and the story is a strange one indeed:
The Rocky Mountain locust (Melanoplus spretus) was the major form of locust that ranged through almost the entire western half of the United States (and some western portions of Canada) until the end of the 19th century. The insect may have produced larger swarms than any other type of locust. One 1874 sighting famous to entomologists recorded a swarm 198,000 square miles (513,000 km²) in estimated size