Students observe external features of monarch eggs, larvae, chrysalises and butterflies. These features include familiar structures such as wings and legs, as well as small and unfamiliar structures such as mandibles and spiracles. Some features are easily seen without magnification, but it is helpful to use magnifying glasses , a stereomicroscope or a Video Flex® camera for these studies. While students are observing structures, they can sometimes relate them to functions they serve in the animal's life. For example, the larva lays down a silk trail from spinnerets located near its mouth. Then the legs and prolegs can attach to the silk and the larva can walk on smooth vertical surfaces or upside down on plant stems.

Children initially identify basic features of the monarch, but refine their knowledge of insect anatomy by learning about function of these features and others. They learn to identify specialized structures of monarch larva, chrysalis and butterfly (for example, the spiracles involved in gas exchange).