Coloured scanning electron micrograph (SEM) of a fruit fly (Drosophila melanogaster) emerging from its puparium (brown), the process known as eclosion. The fibrous background is paper. The puparium is the hardened outer skin of the final larval instar, inside which the larva undergoes metamorphosis. Most of its cells die, but some (in regions called imaginal discs) develop the adult structures such as compound eyes (red), legs, antennae or wings. The fly escapes by inflating its head to split the puparium. Still with a soft exoskeleton, it thrusts its head forwards and performs pulsed contractions of its body to free itself. Also known as the vinegar fly, D. melanogaster is a model organism for research due to its short life cycle and simple genetic makeup. Many varieties exist, with differing eye and body colours. This fly is the variety Oregon R. The colours are false. Magnification: x45 at 10x8.