Widely separated populations of Aulocara elliotti (Thomas) were found to vary in several respects, but these variations could not be correlated to changes in density among the populations studied. When widely separated populations or segments of what is usually considered to be a single population were subjected to applied stresses of temperature extremes and starvation, their resistance was found to be population (area) dependent. Mechanisms such as genetic segregation, physiological degradation, and environment are discussed as possible explanations of population response and behavior. No single factor appears to provide a reasonable explanation. A case is presented to demonstrate the existence of subpopulations or even separate populations within a narrowly denned area of occurrence.