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Species Strymon melinus - Gray Hairstreak - Hodges#4336

Gray hairstreak - Strymon melinus Butterfly - Strymon melinus - male Gray Hairstreak caterpillar - Strymon melinus Hairstreak Butterfly Laying Eggs - Strymon melinus - female Grey Hairstreak ? - Strymon melinus Blue-grey butterfly with orange markings  - Strymon melinus IMG_09152019_AC_8273 - Strymon melinus Butterfly on Purple Loosestrife - Strymon melinus
Show images of: caterpillars · adults · both
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Lepidoptera (Butterflies and Moths)
Superfamily Papilionoidea (Butterflies and Skippers)
Family Lycaenidae (Blues, Coppers, Hairstreaks, Harvesters)
Subfamily Theclinae (Hairstreaks)
Tribe Eumaeini
Genus Strymon
Species melinus (Gray Hairstreak - Hodges#4336)
Hodges Number
Other Common Names
Common Hairstreak, cotton square borer (caterpillar)
Explanation of Names
Strymon melinus (Hübner, 1818)
Probably from Greek melinos (μελινός)- "ashen"
Wingspan: 7/8 - 1 3/8 inches (2.2 - 3.5 cm).
One tail on hindwing. Upperside blue-gray with large red spot near tail. Underside of spring/fall form is dark gray, summer form is paler gray. Relatively straight postmedian line is white, bordered with orange on the inside edge. Usually an orange patch at back of head, and males most often have orange abdomens.

Caterpillar is variably green, has long hairs on dorsum, fairly distinctive in this family (1).
southern Canada to Venezuela - Map (MPG)
Open, nonforested sites; common in disturbed, weedy areas.
Two flights from May-September in the north, three-four flights from February-November in the south.
Caterpillar hosts: Flowers and fruits from an almost endless variety of (usually) herbaceous plants; most often from pea (Fabaceae) and mallow (Malvaceae) families including beans (Phaseolus), clovers (Trifolium), cotton (Gossypium), and mallow (Malva).
Adult food: Nectar from many flower species including dogbane, milkweed, mint, winter cress, goldenrod, tick trefoil, and white sweet clover.
Life Cycle
Males perch all afternoon on small trees and shrubs to seek receptive females. Eggs are laid singly on flowers of host plant. Young caterpillars feed on flowers and fruits; older ones may eat leaves. Caterpillars are sometimes attended by ants, which receive a sugary solution from the dorsal nectary organ (Idaho Museum of Natural History, (2), BugGuide photos). Chrysalids hibernate (1) (3).

Caterpillar with attendant ant, larva inside pole bean, larva, pupa, emerged adult
The most widespread hairstreak in North America.
Print References
Wagner, p. 103, illustrates larva (1).
Allen, pp. 99-100, plate 10--imago, 34--larva, 46--pupa (2)
Scott, #358, gives extensive list of hostplants (3).
Internet References
Idaho Museum of Natural History, Digital Atlas of Idaho, species account for Gray Hairstreak--mentions association with ants
Zuträge zur Sammlung exotischer Schmettlinge, p.22    Hübner's original description of the species (in German, with Fraktur letters)
Works Cited
1.Caterpillars of Eastern North America
David L. Wagner. 2005. Princeton University Press.
2.The Butterflies of West Virginia and Their Caterpillars
Thomas J. Allen. 1998. University of Pittsburgh Press.
3.The Butterflies of North America: A Natural History and Field Guide
James A. Scott. 1992. Stanford University Press.