The Parts of a Butterfly

Whether large (like a monarch butterfly) or small (like a spring azure), butterflies and moths share certain morphological features. The diagram highlights the basic common anatomy of an adult butterfly or moth. The sections, divided according to butterfly or moth parts, provide more specific descriptions of the various appendages of these beautiful insects. The parts are indicated by numbers, which correspond to the sections.

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Forewings

Parts of a butterfly. — Flickr user B_cool (CC license); modified by Debbie Hadley, WILD Jersey

The forewings are the anterior wings, which are attached to the mesothorax (the middle segment of the thorax). Scent scales—modified wing scales on the forewing of male butterflies and moths—release pheromones which are chemicals that attract females of the same species.

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Hindwing

The posterior wings, attached to the metathorax (the last segment of the thorax), are called the hindwings. Hindwings are actually unnecessary for flight but essential for the execution of normal evasive flight in butterflies and moths, according to a 2008 paper by Benjamin Jantzen and Thomas Eisner, published in PNAS. Indeed, moths and butterflies can still fly, even if their hindwings are cut off, they note.

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Antennae

Extreme Close up of a Tiger Mimic Butterfly (mechanitis_polymnia) — Tiger Mimic Butterfly.
Douglas Sacha/Getty Images

The antennae are a pair of sensory appendages, used primarily for chemoreception, the process by which organisms respond to chemical stimuli in their environments that depends primarily on the senses of taste and smell. As with most other arthropods, butterflies and moths use their antennae to detect odors and tastes, wind speed and direction, heat, moisture, and touch. The antennae also help with balance and orientation. Interestingly, the antennae of a butterfly have rounded clubs on the ends, whereas, in moths, they are often thin, or even feathery.

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Head

Close up of butterfly — Dan Wang/Getty Images

The butterfly or moth's almost spherical head is the location of its feeding and sensory structures, and it also contains its brain, two compound eyes, the proboscis, the pharynx (the start of the digestive system), and the point of attachment of its two antennae.

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Thorax

Malachite Butterfly Extreme Close Up — Malachite Butterfly.
Ger Bosma/Getty Images

The second section of the butterfly or moth body, the thorax consists of three segments, fused together. Each segment has a pair of legs. Both pairs of wings also attach to the thorax. In between the segments are flexible areas that allow the butterfly to move. All three parts of the body are covered in very small scales, which give the butterfly its color.

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Abdomen

Close up of the Clipper Butterfly — Clipper Butterfly.
Jean-Philippe Tournut/Getty Images

The third section is the abdomen, which consists of 10 segments. The final three to four segments are modified to form the external genitalia. At the end of the abdomen are the reproductive organs; in the male, there is a pair of claspers, which are used to hold on to the female during mating. In the female, the abdomen contains a tube made to lay eggs.

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Compound Eye

extreme close up of a butterfly eye — Tomekbudujedomek/Getty Images

The butterfly and moth's large eye, also called a compound or third eye, senses light and images. The compound eye is a collection of thousands of ommatidia, each of which acts as a single lens of the eye. Ommatidia work together to enable the butterfly to see what's around it. Some insects may have just a few ommatidia in each eye, while butterflies and moths, as noted, have thousands.

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Proboscis

Border butterfly, Iguazu falls — Border butterfly.
Mario Cugini/Getty Images

The butterfly or moth's collection of mouthparts, the proboscis, is modified for drinking, curls up when not in use, and extends like a drinking straw when it feeds. The proboscis is actually made up of two hollow tubes that the butterfly (or moth) can uncoil its proboscis when it wants to feed.

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Foreleg

Red Admiral Butterfly Macro — Red Admiral Butterfly.
Simon Gakhar/Getty Images

The first pair of legs, attached to the prothorax, is called the forelegs. The butterfly actually has six jointed legs, which, in turn, have six parts, the coxa, femur, trochanter, tibia, pretarsus, and tarsus. The legs of a butterfly have chemoreceptors on its tarsal segments. This helps them to smell and taste.

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Midleg

Close up of a Machaonas (Papilio Machaon) Swallowtail Butterfly on a plant — Machaonas (Papilio Machaon) Swallowtail Butterfly.
Eve Livesey/Getty Images

The middle pair of legs, attached to the mesothorax, are the midlegs. Butterflies can locate food sources by simply using their chemoreceptors on their legs. Female butterflies, for example, can identify if a plant is a good location on which to lay eggs. The plant releases a chemical after the female butterfly drums its legs on a leaf, which the female butterfly picks up with its chemoreceptors.

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Hind Leg

Butterfly on flowers — Arto Hakola/Getty Images

The last pair of legs, attached to the metathorax, are the hind legs. The middle and hind legs are the pairs that are made for walking. The muscles of the thorax control the wings and legs.

View Article Sources

“All about Butterflies.” Albert Bandura Autobiography.
Jantzen, Benjamin, and Thomas Eisner. “Hindwings Are Unnecessary for Flight but Essential for Execution of Normal Evasive Flight in Lepidoptera.” PNAS, National Academy of Sciences, 28 Oct. 2008.
Smart, Paul 1977. The Illustrated Encyclopedia of the Butterfly World, Chapter 2. Chartwell Books.
“Things To Know About Butterfly Body Parts.” Thefollisreport, 27 Mar. 2017.