A variety of metamodeling concepts, methods, and tools are available to today's modeling and simulation community. The Model Driven Architecture (MDA) framework enables modelers to develop platform independent models which can be transformed to platform-specific models. Considering model development according to the MDA framework, structural metamodeling is simpler as compared to behavioral metamodeling. In this paper, we shed light on and introduce behavioral metamodeling for atomic DEVS model. Behavior specification for an atomic DEVS model is examined from the standpoint of the MDA framework. A three-layer model abstraction consisting of metamodel, concrete model, and instance model is described from the vantage point of the DEVS formalism and the Eclipse Modeling Framework (EMF), a realization of MDA. A behavioral metamodel for atomic DEVS model is developed in EMF Ecore. This metamodel is introduced to complement the EMF-DEVS structural metamodeling. Some observations are discussed regarding behavioral metamodeling, model validation, and code generation.