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Edward's hairstreak

Edward's hairstreak (Satyrium edwardsii)
Photo © Mary Kay Rubey

Features and Behaviors

Edwards’ hairstreak butterfly has a wingspan of about one and one-fourth to one and one-half inches. A tail is present on the lower edge of the hindwing. The lower side of the hindwing is pale brown and has a blue spot that is not outlined with orange. There is also a row of dark spots on this side of the hindwing. The caterpillar has a black head. Its body is brown with pale yellow marks.

Edwards’ hairstreak butterfly may be found statewide in Illinois. It lives in forested or sand areas where it feeds on black oaks or on scrub oaks of the sand areas. The life cycle includes egg, larva, pupa and adult stages. The larva, or caterpillar, feeds at night and may hide during the day in an ant nest at the base of its host tree. Edwards’ hairstreak is active from June through July. The species overwinters in the egg stage.

Illinois Range


​Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Lepidoptera
Family: Lycaenidae

Illinois Status: common, native