Abstract: A method, compositions and apparatus are disclosed for causing the death of pupating insects, especially fleas, at all stages of the life cycle. The invention includes by both direct and residual insecticidal extermination of juveniles, adults, larvae and eggs, and also provides an environment of elevated humidity, temperature and pressure around pupal cocoons to cause the cocoons open quickly, so that the emergent insects are killed by residual insecticide, thus providing complete termination of an insect infestation and prevention of development of new infestations from subsequent emergence of metamorphosed insects from surviving pupa. Extermination occurs from the simultaneous application of a "residual" adulticide, a "residual" larvacide, and high temperature hot water under pressure to the infested location.