The first part of this work was published in 1988, the second in 1993, after which administrative duties at the Muséum National d'Histoire Naturelle prevented the author from working on this manuscript for two decades. From 2003 onwards he has been able to consult collection at various museums and undertake further collection work. Part 3, then, presents the reorganisation of the systematics of the butterfly genus Morpho resulting from this work. It treats the remaining subgenera Pessonia, Grasseia and Morpho, and provides a separate chapter with addenda to parts 1 and 2 based on new information that has been gathered in the intervening time.