It is a well known fact that the beetle. Scaphinotus interruptus (Men.), feeds on slugs. Lange (1941) in his study of artichoke pests states. "The large carabid beetle, Scaphinotiis interruptus (Men.), is a very effective natural enemy of slugs, and has been found preying on both the garden [Deroceras agreste (Linneaus)] and greenhouse slug [Milax gagetes (Muller)] in most of the artichoke-growing areas." Essig (1926), concerning members of the genus Scapinotus found in California, states, "The writer has many times observed different ones of these species feeding on the small gray garden slug, Agriolimax agrestis (Linn.) [Deroceras agreste] in the San Francisco Bay region." To gather specific information about this predaceous carabid beetle field and laboratory observations were undertaken on the Mills College campus and in the immediate surrounding area in Oakland, California. Data are included here illustrating the manner in which this beetle attacks its prey in the field ; indicating the number and kinds of mollusks consumed over stated periods of time ; and giving the food-weight-beetle-weight relationship.