The development of insects such as the fruit fly, drosophila, consists of two phases. the larva emerges from the egg and after a period of growth, changes into an adult. the adult insect is very different from the larva. the precursor cells for the adult structures are present in small clusters (the imaginal discs) inside the larva. during the larval stage the disc cells do not play a role. however, during metamorphosis the disc cells start to divide and develop into specific adult structures. compare and contrast the drosophila development to the development of c. elegans.