As you know, holometabolous metamorphosis is one of the most ghastly things in nature. The larva is driven by chemical imperatives to entomb itself alive in its own final skin. Then the absence of a protective juvenile hormone permits the activation of the imaginal discs embedded in its infant flesh. These spew forth a torrent of enzymes which tear apart most of its cells in a sort of quasi-digestive self-immolation, leaving it as basically a shiny bulging sac of goo in which the discs float, spinning new arts and organs round themselves out of the dissolved ex-caterpillar. When they've finished, the imago will explode out of its old skin like a John Carpenter special effect. Its wings at this point are still soft and soggy, with the consistency of used kitchen paper, so it'll have to hang upside down, dry off and pump hemolymph into its wing-veins before it can take off and make innocent humans coo over its beautiful colours.