Hatching of the Comma
I've simplified the stages a little.
| 1. The pupa has just split open. |  |
2. The adult butterfly pushes the case open. |  |
| 3. Now it pulls itself free from the case. |  |
4. Its body is full of fluid. |  |
| 5. The fluid is pumped into the wings. The wings are two membranes which effectively make a bag. |  |
6. Finally the wings are straight. There is a short drying period before the Butterfly is ready to fly. |  |