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Insect Identification Key
Order Lepidoptera: the butterflies and moths

Various lepidopterans
These are four examples of the order Lepidoptera. Clockwise from upper left, the insects are: monarch butterfly, female (Danaus plexippus); common sulphur (Colias philodice); moth; spicebush swallowtail (Papilio troilus). Monarch, moth and common sulphur collected and identified by: Sara Mitchell. Spicebush swallowtail collected and identified by Alma Frazier. Photo credit: Amanda McCreless.
Click here to see examples of more butterflies and moths!

Based on your answers to the questions, you have identified your insect as being in the order Lepidoptera!

Members of this order include: butterflies and moths.

Etymology: Lepidoptera comes from the Greek words lepido, which means scale, and ptera, which means wings. This refers to the tiny scales that are present on the wings of butterflies and moths.

General characteristics:

Note: Butterflies and moths have a number of different characteristics.

• Both have two pairs of typically large, broad wings
• In both, the forewings are usually larger and are shaped differently from the hind wings.
• In both, minute scales are present on the wings (you will need a strong hand lens or a microscope to see the scales).
• Both have soft, cylindrical bodies.
• Both typically have coiled mouthparts
• Butterflies have slender bodies.
• Butterflies have clubbed antennae. These are antennae that are swelled at the tips. Sometimes the swelling is quite obvious, but sometimes it is slight.
• Butterfly forewings overlap the hindwings, but they are not linked as moth wings are (see below).
• Moths typically have stout bodies.
• In moths, the forewings and the hindwings are linked together with a small spine or bristle (called a frenulum) on the hind wing that latches onto a small hook (called a retinaculum) on the forewing.
• In moths, the antennae are not clubbed. Moth antennae come in a variety of shapes, including thin and threadlike, and broad and feather-like.
• Both exhibit holometabolous metamorphosis (egg — larvapupa — adult)

Number of species worldwide: about 150,000

Click here to see examples of more butterflies and moths!


Kingdom Animalia
   Phylum Arthropoda
      Class Insecta
         Order Lepidoptera

For a list of all of the orders in this key, click here: List of Orders.

Classification note: Butterflies are not flies. True flies are in the order Diptera. Usually insects with “fly” written as a separate word (as in house fly, deer fly, etc.) are true flies. Others in which the “fly” is not a separate word, such as butterfly, stonefly and firefly, are not true flies.

Oops! If this doesn't appear to be the order for your insect, go back through the key and look more carefully at your insect while answering the questions again. Your perseverance will reward you!

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Photos at the top of this website are by: Leslie Mertz, Ph.D.,

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