Abdomen - the hind part of the body on the caterpillar and the butterfly. All insects have one!

Antennae (singular antenna) - sensory appendages attached to the head of some adult insects. Antennae are used for the sense of smell and balance. Butterflies have two segmented antennae with a small club at the end of each. A club is the thickened end of a butterfly's antenna.

Compound Eyes - found on the butterfly's head. Thousands of tiny lenses help the butterfly see in all directions, and recognize color and pattern and movement.

Forewings - butterflies have two sets of wings and the forewings are those found closest to the head.

Head - is the front section of the butterfly, representing one of the three main body parts found in all insects. In the head are found the: antennae, eyes, palpi, and proboscis.

Hindwings - butterflies have two sets of wings, and the hindwings are those found closest to the very end of the abdomen.

Proboscis - a tube-like, flexible "tongue" that butterflies and moths use to sip their liquid food (usually flower nectar or the liquid from rotting fruits). The proboscis uncoils to sip food, and coils up again into a spiral when not in use. The lepidopteran with the longest proboscis is the hawk moth.

Thorax - the three front segments of the caterpillar, each segment with a pair of legs. The front part of the butterfly's body.

Wing Viens - there are numerous veins that are found in wings of butterflies, running from the wing base out to the final margins. These veins are very important in the classifications of different species of butterflies.

Abdomen - is the segmented tail area of an insect. It contains the heart, reproductive organs, and most of the digestive system.

Abdominal Prolegs - are the peg-like legs on the abdomen (hind region) of the caterpillar. These legs have small hooks on them. These legs also disappear in the adult butterfly.

Anal Prolegs - are a pair of stumpy legs at the very end of a caterpillar's abdomen (hind region). These legs have small grasping hooks on them.

Head - is the location of an insect's brain, two compound eyes, its proboscis, pharynx (the start of the digestive system) the point of attachment of its two antennae, etc.

Mandible - the caterpillar's jaw.

Ocellus - (plural ocelli) Ocelli (also called stemma, pl. stemmata) are small, simple eyes that insects have. They are composed of photo receptors (light-sensitive cells) and pigments. Ocelli are usually located on the caterpillar's head or between an adult insect's two compound eyes.

Palpi - feelers that help the caterpillar "see" where it's going - also found on the butterfly's head.

Setae - (singular seta) Tactile setae are long hairs that are used to sense touch. These hairs are attached to nerve cells, and relay information about touch to the insect's brain.

Spinneret - opening of the silk gland, found on the caterpillar's lower lip. It's used to create the silk pad to which the chrysalis attaches.

Spiracles - breathing holes. Found in pairs - one on each side of all segments of the caterpillar except the second, third, and the last. Spiracles are also found on the chrysalis and butterfly.

Tentacles - Some caterpillars have tentacles (also known as filaments) on their bodies. These fleshy appendages provide sensory information for the caterpillar. They are often mistaken for antennae.

Thoracic Legs - are the three pairs of jointed legson the thorax (mid region) of the caterpillar. Each of these legs have a grasping hook at the end.

Thorax - is the chest area of an insect. The thorax is divided into three segments; on each segment is a pair of legs. The thorax contains the muscels that make legs move.