The Essig Museum of Entomology on the campus of the University of California at Berkeley houses an active research collection of over 5,000,000 terrestrial arthropods. From humble beginnings as a teaching collection over a hundred years ago, through exponential growth as the California Insect Survey beginning in 1939, the Essig Museum is now one of the largest and most important university-based research collections of insects in North America. Primarily a collection of specimens from the Western Hemisphere, regional emphasis is on the eastern Pacific Rim, in particular California, Mexico, and Central America, and the islands of the central Pacific.