Abstract
Cell dissociates of wing and leg imaginal discs perform, culturedin vivo, disc specific morphogenetic movements leading to their aggregation into layers and vesicles. These histological patterns correspond directly with the final cuticular patterns which appear after metamorphosis of the same implants. The reaggregation into layers is achieved before the entry of the blastems into metamorphosis, and reflects the existence of traits of differentiation in the isolated imaginal disc cells. The bearing of selective affinity and reaggregation on cell differentiation of imaginal discs cells is discussed.