This was more time consuming to photograph than I thought it would be. What I've learned after 6 caterpillars over the past month is weather they're hatching from a chrysalis (left) or about to begin one (right), all major changes take place during the daylight hours.
When ready to morph into a chrysalis the caterpillar will hang upside down for a while and form the letter J (see above). The green lines toward the head tell you they're going to morph, but if it's already getting dark out this isn't going to happen until bright and early the next morning.
The initial change is incredibly quick to start out. I woke up very early this morning to find a caterpillar hanging in the J shape as it had been the night before. Sometime in the next 10 minutes I stopped watching it had turned into this! I believe it shed it's skin off revealing the bright green flesh beneath.
The head is towards the bottom where several yellow-gold dots are forming. The wings also form now and their development will slowly cover most of the body. What remains of it's suction-cup feet dissolve away. Also note the more solid white line in the middle of the body. We'll follow it's progress farther on.
The next hour seems mostly devoted to expanding the wings, and forcing most of the body fat (mass?) towards the top. This is done through a series of wiggles. That white line slowly makes it's way higher and higher as this goes on.
Slowly all the pieces come together and solidify their final resting place.
Note how high up the white line has risen. That was the half way mark in the caterpillar's body when this began. I can only imagine how inside-out the contents of this insect must be in there. It's has reached it's final shape but there's still some smoothing out to do.
This is what they look like two hours in. The chrysalis becomes more opaque over time and turns a beautiful emerald green color with gold trim and spots.
This image is from last year.
I feel like there should be a trend of women gluing these to necklaces to wear as jewelry for the brief time that they look this pretty.
10 to 14 days later they hatch. This also happens in the early morning, but they'll turn transparent the day before.