Cecropia moth caterpillars molt 4 times before they construct the cocoons inside which they become the pupae that can survive the winter weather. The phases between molts are called “instars”: 1st instar caterpillars have not molted since hatching from the egg, 2nd instar caterpillars have molted once, and 5th instar caterpillars have molted four times and have reached maturity as larvae.

Just at the two-week point since hatching, the first 2nd instar caterpillar has appeared. In appearance it is quite different from the all-black 1st instar hatchlings. It has a greenish-yellow body, but retains the black spicules that serve as its defensive armor.

Cecropia moth larva - 2nd instar caterpillar