Hairstreaks
What are they?
Hairstreaks, along with the blues and coppers, are members of the family Lycaenidae, a large and diverse family of mostly small, but often highly attractive, butterflies. The hairstreaks get their name from the often very fine, hair-like markings on the wings. Many of them sport a 'tail' on the back of each hindwing and these tails, together with bright red or blue markings at their bases, appear to create the impression of a false head. This impression is enhanced further by the butterfly moving the hindwings when at rest to make the tails move like antennae. Having a false head in this way potentially protects the insect by deflecting predator attacks towards a part that, if bitten off, will not cause the demise of the butterfly.
Identification
Some hairstreaks can be tricky to identify when the wings start to get a little worn, later in the season. However, when fresh, most species should be identifiable easily enough by the markings on the underside of the hind wing.
Banded Hairstreak Satyrium calanus
Wingspan: 1.1 inches. Flight time: May to July. Larval foodplant: A range of hardwood trees, especially oaks and hickories. A widespread species in wooded and scrubby areas. In Cape May County, this species is most similar to Striped Hairstreak, from which it can be told fairly easily by the pattern of the underside of the forewing and the lack of a red spot on the front edge of the blue spot on the underside of the hindwing.
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Striped Hairstreak Satyrium liparops
Wingspan: 1.1 inches. Flight time: June to July. Larval foodplant: A range of woody trees and shrubs in the Rose (Rosaceae) and Heath (Ericaceae) families. A widespread species in secondary woodland and scrubby areas. In Cape May County, this species is most similar to Banded Hairstreak, from which it can be told fairly easily by the pattern of the underside of the forewing and the presence of a red spot on the front edge of the blue spot on the underside of the hindwing.
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Brown Elfin Callophrys angustinus
Wingspan: 1.0 inches. Flight time: April to May. Larval foodplant: Woody shrubs in the Heath Family (Ericaceae). Local and most likely to be found in the northern third of Cape May County. Differs from Henry's and Frosted Elfins by having a warm rusty-brown outer third to the underside of the hindwing.
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Hoary Elfin Callophrys polios
Wingspan: 0.9 inches. Flight time: April to May. Larval foodplant: Bearberry (Ericaceae). This species is not currently known to occur in Cape May County and is confined in our area (by the distribution of its food plant) to pine barren habitats in neighboring counties. Generally rare and very local patchily distributed, though good numbers can be found at a few, favored locations. Differs from Frosted Elfin largely by the more extensive pale 'frosting' on the wings. In Hoary Elfin, this frosting extends along the trailing edge of the underside of the forewings and is not confined just to the hindwings.
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Frosted Elfin Callophrys irus
Wingspan: 1.1 inches. Flight time: May to June. Larval foodplant: Members of the Pea Family (Ericaceae), especially Wild Indigo in our area. Widespread but local and often elusive. Most likely to be found in secondary growth areas with open, sandy spots that hold stands of Wild Indigo. Differs from Henry's Elfin by having a black spot in the frosted band towards the rear of the underside of the hindwing (beware of worn individuals where the spot may be far from obvious). In addition, the whitish line running down the underside of the forewing is more irregular in this species, looking rather like a series of joined up dashes.
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Henry's Elfin Callophrys henrici
Wingspan: 1.0 inches. Flight time: April to early June. Larval foodplant: A wide range of woody shrubs and understorey trees. Our commonest elfin and the one most likely to be seen in disturbed or suboptimal habitats. Differs from Frosted Elfin by the lack of a black spot in the frosted band towards the rear of the underside of the hindwing. In addition, the whitish line running down the underside of the forewing is more regular in this species, appearing more like a continuous wavy line.
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Eastern Pine Elfin Callophrys niphon
Wingspan: 1.0 inches. Flight time: April to June. Larval foodplant: Pines, in our region probably mostly Pitch and Virginia Pines. Fairly widespread in wooded or scrubby areas with pines but usually only encountered in small numbers, often singly. Our most attractive elfin with more complex markings on the underside of the wings than other elfins.
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Juniper Hairstreak Callophrys gryneus
Wingspan: 1.0 inches. Flight time: April to May and July to August in two broods. Larval foodplant: Virginia Juniper (Juniperus virginiana). A widespread species which may be found throughout the county but populations vary heavily from year to year and it is not often an easy species to find. The much rarer Hessel's Hairstreak is very similar but has more irregular bands on the wings and a white mark towards the base of the forewing. The white band on the underside of the hindwing is bordered on both sides in Hessel's Hairstreak.
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White M Hairstreak Parrhasius m-album
Wingspan: 1.25 inches. Flight time: April to October in two or three broods. Larval foodplant: The leaves of various oak species. A widespread species but never particularly common. Occurrence around Cape May Point late in the season perhaps involves dispersing individuals from elsewhere. This species has a fabulous, irridescent blue upperside to its wings, but unfortunately it is rarely seen in living individuals! The underside is very similar to Gray Hairstreak, but the white line on the hindwing forms a clear M (or W depending on your angle of view) and there is no black spot behind the red patch (or sometimes just a very small one). Perhaps most obvioulsy, Gray Hairstreak lacks the white mark that White M has towards the leading edge of the underside of the hindwing.
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Gray Hairstreak Strymon melinus
Wingspan: 1.1 inches. Flight time: April to October in two broods. Larval foodplant: An exceptionally wide range of both woody and herbaceous plants. A widespread and often encountered species and probably our most common hairsteak. The underside is very similar to White M Hairstreak, but the white line on the hindwing doesn't forms a clear M (or W depending on your angle of view) and there is an obvious black spot behind the red patch.
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Red-banded Hairstreak Calycopis cecrops
Wingspan: 1.1 inches. Flight time: May to October in two or three broods. Larval foodplant: A range of woody plants, most likely Wax Myrtle and Winged Sumac in our region. A widespread and often encountered species and one of our commonest hairsteaks. Often seen in good numbers nectaring at Sweet Pepperbush flowers in early summer. Readily told from other hairstreaks in our area by the orange-red band that runs across the underside of both fore- and hindwings.
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