During the pupariation to pupation developmental transition period, the respiration of the Flesh Fly, Sarcophaga crassipalpis, undergoes complex but reproducible respiratory patterns. Included in these is a 2 hour pattern we call the pupal respiratory cycles. We have analyzed these patterns for a quantitative description of the CO2 release during this period using a Sable Systems flow through microrespirometer. The results suggest a novel and unique developmentally complex control of respiration that is different from passive ventilation or discontinuous gas exchange reported in other systems. Partial support was provided by HHMI Symbiosis Grant # 52005872.