All photos by Ned Harris.
Again, adults (of the insect variety) have wings.* Butterflies and moths both go through 'complete' metamorphosis: egg - larva - pupa - adult. What the difference, you ask? 'Complete' metamorphosis involves pupating; in essence, pulling the covers over your head, taking yourself completely apart, and building a winged critter out of the goo. The bigger you are going in to the 'take-apart' stage, the bigger you're likely to be coming out. It's like building something with Legos. If you have 100 to work with, you can build something bigger than if you only have 50.
The larvae (caterpillars) of butterflies and moths eat and eat and eat their host plants so that they have as much mass as possible going into the pupa stage. During the pupa stage, insects aren't eating - 'just' taking themselves apart entirely and rebuilding. It's really amazing. Beyond amazing. Awesome, in every possible sense of the word.
*(As is my custom on this blog,) I'm looking at the big picture - of insects, in this case; not every species, not every exception. In my experience, you can go along way in the realm of insects if you know that adults have wings. My apologies to entomologists for the generalizations.