[1] Contained within the body of the larva, there are pairs of discs that will form, for instance, the wings or legs or antennae or other structures in the adult.

It is of interest to entomologists that the kinds of developmental switches that occur are very specific (leg to antenna, for instance).

Study of this phenomenon led to the discovery of the homeobox genes, and started a revolution in the understanding of development in multi-celled animals.

[5] Imaginal cells are tissue-specific progenitors allocated in embryogenesis that remain quiescent during embryonic and larval life.

In late larvae, both populations are activated and proliferate, spread over and replace old branches, and diversify into various stalk and coiled tracheolar cells under control of fibroblast growth factor signaling.