Hessel's Hairstreak

Callophrys hesseli (Rawson and Ziegler, 1950)

Hessel's Hairstreak
Jeffrey Pippen

Insecta (Insects)
Lycaenidae (Blues, Coppers, Hairstreaks, Elfins)
State Protection
Listed as Endangered by New York State: in imminent danger of extirpation in New York. For animals, taking, importation, transportation, or possession is prohibited, except under license or permit. For plants, removal or damage without the consent of the landowner is prohibited.
Federal Protection
Not Listed
State Conservation Status Rank
Critically Imperiled in New York - Especially vulnerable to disappearing from New York due to extreme rarity or other factors; typically 5 or fewer populations or locations in New York, very few individuals, very restricted range, very few remaining acres (or miles of stream), and/or very steep declines.
Global Conservation Status Rank
Vulnerable globally - At moderate risk of extinction due to rarity or other factors; typically 80 or fewer populations or locations in the world, few individuals, restricted range, few remaining acres (or miles of stream), and/or recent and widespread declines.


Did you know?

This is the only butterfly species whose caterpillar feeds exclusively on Atlantic White Cedar.

State Ranking Justification

Although this species is one of just a handful of butterflies on the state endangered species list, nothing is known of its current status in New York. However, there is reason to believe that this species is extirpated from the state. All of the few known occurrences on Long Island were first- discovered about 1980, and since then only one of them has been found to harbor butterflies. At this site only 12 butterflies were collected during seven surveys between 1983-1989 and resurveys in the early and mid-1990s failed to turn up any butterflies at any of the formerly occupied sites. Mosquito spray programs on Long Island are known to kill the butterflies outright (Shapiro and Shapiro 1973) and there are myriad threats to the viability of its white cedar swamp habitat not only on Long Island, but rangewide. Only an estimated 5% of the historical Coastal plain white cedar swamps in New York remain. Past spraying for spongy moths (especially DDT in the 1950s) is believed to have wiped out many colonies (NatureServe 2009).

Short-term Trends

Since the 1980s only one of the known popualtions was found to be inhabited, and no butterflies have been seen at this site since the 1990s, despite targeted searching by experts (NYSDOS 2002). The other known Long Island sites were also searched by experts in the late 1980s and early 1990s without success. One remote inland Atlantic white cedar swamp in Orange County where the species was found in the late 1970s still contains suitable habitat, and might be the most likely place to still harbor this butterfly in New York.

Long-term Trends

Shapiro (1974) reported two sites on the south shore of Long Island; the next mention of this species in New York is from about 1980, when five sites were known in Suffolk County and one in Orange County (Cryan 1985). However, this butterfly has not been seen in New York since the mid 1990s and many experts believe it is probably extirpated from the state.

Conservation and Management


Primary threats to the butterfly include spongy moth and mosquito insecticide spraying, localized collecting pressure and possibly bird predation (NatureServe 2009). The threats to the species' habitat are numerous and both the Atlantic white cedar swamp community (S1) and C. thyoides itself are imperiled (S2) in New York. Only an estimated 5% of the historical Coastal plain white cedar swamps in New York remain (NYNHP 2011a) and over 15,000 acres of inland Atlantic white cedar were converted to agriculture in the Wallkill Valley alone by the 1970s (Karlin 1997). See NYNHP (2011a) for specific ongoing threats to Atlantic white cedar swamp communities.

Conservation Strategies and Management Practices

Regardless of whether this Hairstreak still occurs in New York, all occurrences of Atlantic white cedar swamps, both coastal and inland, should be protected and managed to sustain the cedar trees. See NYNHP (2011a,b) and NatureServe (2009) for management recommendations and further references for manangement techniques in these community types.

Research Needs

It is imperative to ascertain whether this endangered species remains extant in New York. All occurrences of Coastal plain Atlantic white cedar swamps on Long Island as well as Inland Atlantic white cedar swamps in Putnam and Orange Counties should be surveyed during May to early June to determine whether this species remains a part of New York's Lepidopteran fauna.



This species occurs exclusively in coastal and inland Atlantic White Cedar swamps. Sunny glades with flowers within the swamp are favored locations. Adults stray at times up to 1/2 mile to nearby flowers (NatureServe 2009).

Associated Ecological Communities

  • Coastal plain Atlantic white cedar swamp (guide)
    A swamp that occurs on organic soils along streams and in poorly drained depressions of the coastal plain. Atlantic white cedar makes up over 50% of the canopy cover. In mixed stands in New York, red maple is the codominant tree.
  • Inland Atlantic white cedar swamp* (guide)
    A swamp that occurs on organic soils (usually peat) in poorly drained depressions and along pond edges in southeastern New York and northern New Jersey. The characteristic tree is Atlantic white cedar. In mixed stands the codominants are typically red maple, black gum, and eastern hemlock.

* probable association but not confirmed.

Associated Species

  • Lemmer's Noctuid Moth (Lithophane lemmeri)


New York State Distribution

This species is only known from scattered, disjunct areas of Atlantic white cedar swamps on Long Island in Suffolk County. Historically, it may have also occurred in cedar swamps on the south shore of Long Island in Nassau County, as well as at inland Atlantic White Cedar swamps in Orange and Putnam Counties (Shapiro 1974; Vaughn and Shepherd 2005).

Global Distribution

Hessel's Hairstreak is distributed in scattered, disjunct colonies along the Atlantic coastal plain from southern Maine to the Florida panhandle. The greatest density of colonies occurs in from southeastern Massachusetts through Rhode Island to southern New Jersey (Massachusetts NHESP 2007).

Best Places to See

  • Cranberry Bog County Park (Suffolk County)

Identification Comments

Identifying Characteristics

This is a small butterfly (1") with emerald green tailed wings; the upperside is dark brown with few obvious markings, while the underside has a reddish-brown ground color overlaid with with bright bluish green and white spots and lines. The 1/2" larva is deep blusih green with a series of subdorsal lustrous white boomerang-shaped bars on each segment, rendering it cryptic on the host plant (Rawson et al. 1951, MDIFW 2003, Cassie 2011).

Characters Most Useful for Identification

Habitat is the most reliable factor to use, as Junipers are confined to dry Redcedar old fields and ridges, while the Hessel's occupies only Atlantic white cedar swamps.

Best Life Stage for Proper Identification

Adult male.


Butterflies in this genus have been shown to change their tree perch positions in response to the position of the sun, often moving to the tops of the cedars at midday where they form leks, court, mate, and lay eggs (Johnson and Borgo 1976; Cryan 1985). The adults are often first noticed fluttering out from a tree that has been jarred and they remain primarilly within swamps but may travel up to 1/2 mile in search of nectaring plants (MDIFW 2003; Vaughn and Shepherd 2005; Cassie 2011). Adults suffer from bird predation and individuals in this genus only live for several days (Beck and Garnett 1983).


In the wild, caterpillar larvae feed exclusively on new growth of the Atlantic White Cedar (Chamaecyparis thyoides). Adults nectar at flowering bog plants including Cranberry and Highbush Blueberry (Vaccinium spp.), Shadbushes (Amelanchier), Chokeberry (Aronia), and Buttonbush (Cephalanthus) (Cryan 1985).

Best Time to See

Hessel's Hairstreaks are easily overlooked due to low abundance, inaccessibility of the habitat, a short and unpredictable flight season, habit of perching high in the canopy, small size, and cryptic coloration and behaviors. Thus, very little is known of its life history in New York. Adults have been reported from May 23 only. In neighboring states the adult flight season is generally in May and early June (with a peak in late May), earlier into April southward into New Jersey and later in June northward in Maine. Northward from New Jersey a single spring brood is produced, while southward into North Carolina, a summer brood also emerges (MDIFW 2003, Massachusetts NHESP 2007, Vaughn and Shepherd 2005). However, there is some indication that this species may have historically been partially double brooded on Long Island (Cryan 1985). In Massachusetts, eggs are laid on cedar branch tips in late May and following a brief egg stage, larvae feed on new growth of the host plant for about a month, pupating in July. Pupae enter diapuse in July and emerge the following spring (Massachusetts NHESP 2007).

  • Reproducing
  • Larvae present and active
  • Eggs present outside adult
  • Pupae or prepupae present

The time of year you would expect to find Hessel's Hairstreak reproducing, larvae present and active, eggs present outside adult, and pupae or prepupae present in New York.

Similar Species

  • Juniper Hairstreak (Callophrys gryneus)
    Hessel's Hairstreak can be differentiated from its sibling species, the Juniper Hairstreak, by subtle details of the underwing pattern incluidng the outward offset of the first white spot on a band of spots on the underside of the forewing. Habitat is the easiest factor to use, as Junipers are confined to dry Redcedar old fields and ridges, while the Hessel's occupies only Atlantic white cedar swamps. There is strong evidence that this type of habitat segregation is the first step in host race formation, implying that these two species are in the very earliest stages of speciation (Nice and Shapiro 2001; Forsiter 2004; Downey and Nice 2011).

Hessel's Hairstreak Images


Hessel's Hairstreak
Callophrys hesseli (Rawson and Ziegler, 1950)

  • Kingdom Animalia
    • Phylum Arthropoda (Mandibulates)
      • Class Insecta (Insects)
        • Order Lepidoptera (Butterflies, Skippers, and Moths)
          • Family Lycaenidae (Blues, Coppers, Hairstreaks, Elfins)

Comments on the Classification

Many authorities place this Butterfly in the genus Mitoura.

Additional Resources


Beck, A.F., and W.J. Garnett. 1983. Distribution and notes on the Great Dismal Swamp population of Mitoura hesseli. Journal of the Lepidopterists' Society. 37:289-300.

Cassie, B. 2011. Hessel's Hairstreak. Massachusetts Audubon Society Butterfly Atlas. Lenox, MA.

Cryan, J. 1985. Hessel's Hairstreak: endangered cedar swamp butterfly. The Heath Hen 2:22-25.

Downey, M.H., and C.C. Nice. 2011. Experimental evidence of host race formation in Mitoura butterflies (Lepidoptera: Lycaenidae). Oikos. doi:10.1111/j.1600-0706.2010.19290.x.

Forister, M.L. 2004. Oviposition preference and larval performance within a diverging lineage of lycaenid butterflies. Ecological Entomology 29:264-272.

Gifford, S.M., and P.A. Opler. 1983. Natural history of seven Hairstreaks in coastal North Carolina. Journal of the Lepidopterists' Society 37:97-105.

Johnson, K. 1978. Specificity, geographic distributions, and foodplant diversity in four Callophrys (Mitoura) (Lycaenidae). Journal of the Lepidopterists' Society 32:3-19.

Johnson, K., and P.M. Borgo. 1976. Patterned perching behavior in two Callophrys (Mitoura) (Lycaenidae). Journal of the Lepidopterists' Society 30:169-183.

Karlin, Eric F. 1997. The Drowned Lands' Last Stand: An inland Atlantic white cedar swamp in Orange County, New York. Journal of the Torrey Botanical Society. 124(1):89-97.

MDIFW. 2003. Hessel's Hairstreak. Maine Endangered Species Program. Augusta, ME.

Massachusetts NHESP. 2007. Hessel's Hairstreak. Massachusetts rare species fact sheets. Massachusetts Division of Fisheries and Wildlife, Westborough, MA.

NYNHP. 2011a. Online Conservation Guide for Coastal Plain Atlantic White Cedar Swamp. Albany, NY. Available at: http://www.acris.nynhp.org/guide.php?id=XXX

NYNHP. 2011b. Online Conservation Guide for Inland Atlantic White Cedar Swamp. Albany, NY. Available at: http://www.acris.nynhp.org/guide.php?id=XXX

NYNHP. 2011c. Online Conservation Guide for Atlantic White Cedar. Albany, NY. Available at: http://www.acris.nynhp.org/guide.php?id=XXX

NYSDOS. 2002. Division of Coastal Resources. Coastal Fish and Wildlife Habitat Assessment Form: Cranberry Bog County Park.

NatureServe 2009. NatureServe Explorer. An online encyclopedia of life. Arlington, VA. Available at: http://www.natureserve.org/explorer.

New York Natural Heritage Program. 2024. New York Natural Heritage Program Databases. Albany, NY.

Nice, C.C., and A.M. Shapiro. 2001. Population genetic evidence of restricted gene flow between host races in the Butterfly genus Mitoura (Lepidoptera: Lycaenidae). Annals of the Entomological Society of America 94:257-267.

Opler, P.A. and G.O. Krizek. 1984. Butterflies East of the Great Plains, an illustrated natural history. Johns Hopkins University Press. Baltimore. 294pp.

Opler, P.A. and V. Malikul. 1992. Eastern Butterflies (Peterson Field Guide). Houghton Mifflin Company, Boston, Massachusetts. 396 pp. + color plates.

Pyle, R.M., 1981. The Audubon Society Field Guide to North America Butterflies. Chanitcleer Press, Alfred A. Knopf, NY. 916 pp, 759 color figures.

Rawson, G.W., J.B. Ziegler, and S.A. Hessel. 1951. The immature stages of Mitoura hesseli (Lepidoptera, Lycaenidae). Bulletin of the Brooklyn Entomological Society 46:123-130.

Rawson, G.W., and J.B. Ziegler. 1950. A new species of Mitoura from the Pine Barrens of New Jersey (Lepidoptera, Lycaenidae). Journal Of the New York Entomological Society 58:69-82.

Shapiro, A.M. 1974. Butterflies and skippers of New York State. Search 4:1-60.

Shapiro, A.M., and A.R. Shapiro. 1973. The ecological associations of the Butterflies of Staten Island. Journal of Research on the Lepidoptera 12:65-128.

Vaughn, D.M., and M.D. Shepherd. 2005. Species profile: Mitoura hesseli. In Shepherd, M.D., D.M. Vaughn, and S.H. Black (Eds.). Red List of Pollinator Insects of North America. The Xerces Society for Invertebrate Conservation, Portland, OR.


About This Guide

This guide was authored by: Jeffrey D. Corser

Information for this guide was last updated on: August 30, 2011

Please cite this page as:
New York Natural Heritage Program. 2024. Online Conservation Guide for Callophrys hesseli. Available from: https://guides.nynhp.org/hessels-hairstreak/. Accessed May 26, 2024.