The development, population dynamics, and predation on the eggs and first instars of the house fly,Musca domesticaL., by the manure-inhabiting beetleCarcinops pumilio(Erichson) were simulated in a computer model. Model features include: nonlinear development of beetles and flies, fecundity as a function of beetle density, and predation rate as a function of beetle and fly density. All these processes depend on temperature, which can be set to a constant value or read from a file of variable temperatures. The model includes a management component that incorporates the effects on house fly and beetle populations of various insecticide and manure-removal strategies for fly control. Examples of the results of simulating various management regimes are presented.