Coloured scanning electron micrograph (SEM) of a fruit fly (Drosophila melanogaster) in the act of eclosion. Shown is an open puparium (pale green) on a paper background, with the inflated head of the emerging fly. The puparium, the hardened skin of the final larval instar, is the enclosure in which the larva undergoes metamorphosis. This involves the death of many cells and the development of new adult organs from cellular regions called imaginal discs. When ready to emerge, the fly inflates its head to split the puparium surface. Here, mid process, the head shows a prominent dome. The exoskeleton is still flexible; the insect escapes by pulsed contractions of its body. Once free, the head assumes its final shape, the wings expand, and the exoskeleton hardens. D. melanogaster is a model organism for genetic study, with a short life cycle and only four pairs of chromosomes. Magnification: x96 at 10x8.