Lycaenidae: Gossamer wings

The Lycaenidae or Gossamer wing family includes the coppers, hairstreaks, blues, and azures. Their common name refers to the flimsy, delicate wings of many species.


Males are usually bright blue or copper/golden, sometimes with a metallic gloss. Adults are small, usually under five cm. Adult lycaenids have forelegs that are not usable for walking. Their eyes are indented next to the antennae and their face is taller than the width between their eyes.

Adult individuals often have hairy antenna-like tails complete with a black and white annulated appearance. Many species also have a spot at the base of the tail.

The Coppers (Lycaeninae)

Ruddy Copper (Lycaena rubidus) on Lomatium triternatum Nineleaf Biscuitroot. Photo by Walter Siegmund.

This subfamily’s common name comes from from the copper-colored wings of many of its member species.

These are fast-flying butterflies that usually appear in meadows, marshes, and other open areas.


In most species, the upper surfaces of the wings have a bright to dull copper sheen. Males of most species are copper, blue, or some metallic pattern, while females are typically much paler or colorless.

Host plant

Larvae feed on leaves of docks, knotweed, buckwheat, cinquefoil, gooseberry, currant, and redberry.

The Blues (Polyommatinae)

These butterflies can be found in openings and along the edges of deciduous woods, old fields, wooded freshwater marshes and swamps. Males patrol and perch all day but are most active from midafternoon until dusk.

Spring Azure (Strymon melinus) butterfly on rose
Spring Azure (Strymon melinus) butterfly on rose along road above Wawawai Co. Park, Whitman Co., WA USA (photo: T.D. Hatten)

These are smallish butterflies with a wingspan of 7/8 – 1 3/8 inches.

Upperside of males are blue, while females have some black at the outer edge of their forewing.  Underside hindwings are gray-white with faded small black dots, darker gray with larger black spots, or with blotches and black margins in the center.

Host plants

Caterpillars feed on a variety of woody shrubs and occasionally herbs including dogwood (Cornus florida), New Jersey tea (Ceanothus americana), meadowsweet (Spiraea salicifolia), and Collinsia. Many species’ larvae are tended by ants.

Adults nectar on dogbane, privet, New Jersey tea, blackberry, common milkweed, and many others.

The Hairstreaks and Elfins (Theclinae)

Sheridan's Green Hairstreak (Callophrys sheridanii)
Sheridan’s Green Hairstreak (Callophrys sheridanii) Photo by Walter Siegmund.

Although this is primarily a tropical family, a few of these small- to medium-sized butterflies do make it as far north as Idaho and Washington.

They are often found on flowers in meadows, along roadsides, and in other open areas.


Their common name comes from the characteristic white “hairline” across the ventral hindwing. The eyes are hairy, and they often have two or three hairlike tails on their hindwings.

Host plants

Larvae feed on a wide variety of plants; usually woody trees or shrubs, including oaks, willow, buckbrush, and chokecherry.