Papilio glaucus

Two broods: late April to early July, and July through September.

Deciduous woods, woodland edges, river valleys, swamps, parks, suburbs.

3½″ to 5½″ wingspan

This is a large, familiar, swallowtail butterfly. It has a wingspan of 3½″ to 5½″.

The upperside of the forewing is yellow with black “tiger” stripes and a wide black border with small yellow spots. The hindwing is yellow with a central black stripe and a wide black border with larger yellow spots. The inner margin has an orange spot half surrounded by blue scales. The hindwings have “tails”.

The underside of the forewing is paler yellow with black stripes and a wide black border with a band of disconnected yellow spots. The hindwing is yellow with a central black stripe and a wide black border with an outer row of yellow-and-orange spots and an inner row of blue spots.

Females have two forms. The yellow form female is similar to the male but with much more blue scaling in the black border. The hindwings have an orange or yellow-and-orange spot in the black margin where the forewing and hindwing meet. The black form female has black forewings and blue-tinged black hindwings. The hindwings have more blue scaling and an orange or yellow-and-orange spot in the black margin where the forewing and hindwing meet. The blue on the wings is not iridescent. Black form females are common in the south, uncommon in Minnesota.

The caterpillar is green and smooth, with no spines or hairs. There are small eye-like spots on the third thoracic segment with a black and white pupil.

Black swallowtail (Papilio polyxenes) has 2 rows of yellow spots across both wings and a yellow subapical spot on the forewing.

Canadian swallowtail (Papilio canadensis) is smaller and less yellow above. The submarginal band on the underside of the forewing is continuous, not broken into spots. It is found in the northern half of the state.

Black cherry (Prunus serotina), chokecherry (Prunus virginiana), American basswood (Tilia americana var. americana), birch (Betula), ash (Fraxinus), poplar (Populus), plains cottonwood (Populus deltoides var. molinifera), mountain ash (Sorbus), and willow (Salix).

Flower nectar of black cherry (Prunus serotina), blazing star, ironweed, joe-pye weed, lilac (Syringa vulgaris), milkweed (Asclepias), orange hawkweed (Hieracium aurantiacum), phlox, red clover (Trifolium pratense), thistle, and wild bergamot (Monarda fistulosa ssp. fistulosa).

Males emerge in the spring shortly before the females. The congregate, often in large groups, at mud puddles where they replenish moisture and minerals lost during metamorphosis.

Individuals overwinter as a chrysalis.