The study of ecdysis has undergone resurgence over the past 10 years, revealing an unexpected richness of hormonal signals that orchestrate this behavioral sequence. While much of the initial work was carried out on Manduca, studies on Drosophila are of growing important in testing the role of key components in the control system and in the discovery of new players. The first part of the talk will integrate results from various labs to illustrate the principles that organize the ecdysis control circuitry. A key aspect of this system is the positive feedback interaction between ecdysis-triggering hormone (ETH) and eclosion hormone (EH). The two hormones provide avenues for the inflow of information about declining steroid titers and developmental progression along one pathway versus proximate behavioral stimuli along the other. The proper mix of stimuli result in EH-ETH surge that drives one phase of the behavior and also primes the modulatory system that will drive the next phase, but only after a delay encoded by the properties of inhibitory components. The second part will focus on recent studies on the tanning hormone, bursicon, and its role in controlling the terminal phases of the ecdysis sequence.