Butterfly exiting from chrysalis. During exit fluid from butterflies abdomen was not released into wings.When everything goes as planned this fluid flows through the black vein into the wings and elongates them. This happens in 10 minutes. You literately see them grow in front of your eyes. Wings then dry and become stiff. This takes two hours. They are most vulnerable to predators at this time. After all of this they still need to learn how to fly.