Above is the life cycle of a monarch butterfly. Once the female lays an egg on a milkweed leaf, the journey begins.

 

The egg stage lasts between 3-6 days, depending on temperature. The hotter the temperature the faster the egg, caterpillar and chrysalis develop.  Once the caterpillar (also called a larva) hatches from the egg, it is considered a first instar, which is a stage of development for caterpillars. Caterpillars in this stage are so tiny, you can't see many details without a hand lens. When they hatch they are a cream color, but once they begin eating milkweed, the black stripes begin to show almost immediately, followed by faint yellow stripes a little later.  Once the caterpillar molts (or sheds the skin it has outgrown) for the first time, it gets bigger and becomes a second instar. Caterpillars in this stage are still very tiny, and require a hand lens to see details, other than the stripes. The next stage after the second molt, is the third instar. This stage is when caterpillars have grown large enough to see details with the naked eye, and not a hand lens. The next stage and third molt will become the fourth instar. The fourth instar then molts and the caterpillar enters its fifth instar stage, which is the last stage as a caterpillar. This is also the longest instar stage, and a very important one, since they are eating as much as possible to pass all of the fat, protein and toxins they've stored by eating milkweed on to the adult monarch. Once it molts for the fifth and final time it enters the pupal stage. This is when the caterpillar changes completely. First, they enter the "J" stage, where a great deal of change happens before it sheds that final skin and becomes a chrysalis (also called a pupa). The chrysalis starts out as emerald green, and when the pigment of the butterfly's wings can be seen clearly through the chrysalis, the adult butterfly ecloses (or emerges). This stage lasts between 7-14 days (again, depending on temperature!). Because monarchs go through all four stages in their life cycle, it is known as "complete metamorphosis."  

 

Note: Pictured at the center of the life cycle is milkweed. Without it, monarchs cannot survive.