Step 1: After hatching from an egg, the caterpillar (larva) feeds on plants from the parsley family, including carrots, dill, Queen Anne's Lace, and others. When threatened, the caterpillar emits a foul tasting/smelling toxin from an orange, V-shaped organ near the head called an osmeterium.
Step 2: After molting several times, the caterpillar forms a chrysalis (pupa) on a sturdy object, attaching it with silk. When first formed, the chrysalis is pale green, and the soon-to-be butterfly develops within. After several weeks, just before the butterfly emerges, the chrysalis turns clear and the butterfly inside can be clearly seen.
Step 3: The newly emerged butterfly cannot yet fly. It must first pump fluid from its swollen abdomen through the veins in its wings. As the fluid flows through the veins, the wings expand, and eventually the veins harden to provide rigid structure for the wing membrane.
Step 4: The transformation is complete. Rather than chomping on vegetation (as it did in its larval stage), the adult butterfly will use a long proboscis, which is kept rolled up when not in use, to drink nectar and other fluids. Now, all that is left to complete the life cycle is for the adult to mate and lay eggs, and the cycle will start anew.
