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Montana Field Guides

Eastern Tailed-Blue - Cupido comyntas
Other Names:  Everes comyntas

Native Species

Global Rank: G5
State Rank: SNR

Agency Status

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General Description
[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002] Forewing 1.1-1.4 cm. Tailed. Uppersurface of male iridescent blue, usually one orange spot at base of tail; female brown, with two orange spots at base of tail. Undersurface of hindwing pale gray with distinct rows of black spots, black bar at end of cell, 2 larger orange spots on outer margin (one at base of tail).

Several flights; May to October in the north, February to November on the Gulf Coast, mid-May to mid-September in Colorado, March to September in California (Scott 1986). Continouously brooded during warm weather (Glassberg 2001). Early April to early August in Oregon and Washington (Pyle 2002), mid April to mid-June and July to September in Oregon (Warren 2005), mid-June to mid-July in British Columbia (Guppy and Shepard 2001).

Diagnostic Characteristics
Best determined externally by the undersurface of hindwing pale gray with distinct rows of black spots, black bar at end of cell, 2 larger orange spots (not one as in C. amyntula) on outer margin (one at base of tail).

Species Range
Montana Range Range Descriptions

All Ranges
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Range Comments
Throughout eastern North America from southern Canada to the Gulf states, west through the Dakotas, Nebraska, Oklahoma to central Colorado; isolated populations (probably introduced) through the Pacific Coast states from southern California to Canada (southeastern British Columbia). Also western Texas, western New Mexico and southeastern Arizona south through Mexico to Costa Rica (Scott 1986; Opler and Wright 1999; Glassberg 2001; Guppy and Shepard 2001; Pyle 2002); 1310 m to 2134 m elevation in Colorado (Brown 1957; Scott and Scott 1978), sea level to 1219 m elevation in Oregon (Warren 2005). In Montana, no records through 1993 (Kohler 1980; Stanford and Opler 1993), one report sometime since (apparently lacking details) from Mineral County. Locally rare to locally uncommon in the west (Glassberg 2001).


Open weedy sites, lowland riparian areas, vacant lots, canals, fallow fields, riverbanks, moist meadows, woodland clearings (Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002). Habitat in Montana not described but probably similar.

Food Habits
Larval food plants diverse, include Astragalus, Baptisia, Desmodium, Galactia, Lotus, Lathyrus, Lespedeza (several species), Lupinus, Medicago, Melilotus, Phaseolus, Trifolium (several species), and Vicea (several species) (Scott 1986, 1999, 2006; Warren 2005; James and Nunnallee 2011). Adults feed on flower nectar (including Ammannia, Arnoglossum, Asclepias, Bolonia, Cardamine, Ceanothus, Cercis, Cicuta, Cirsium, Claytonia, Coreopsis, Crotalaria, Dalia, Delphinium, Erigeron, Eryngium, Eupatorium, Euthamia, Fragaria, Geranium, Lespedeza, Lindernia, Lobelia, Lotus, Ludwigia, Lycopus, Medicago, Melilotus, Nothoscordum, Oxalis, Phyla, Polygonum, Potentilla, Pycanthemum, Ratibida, Rudbeckia, Scrophularia, Solidago, Symphyotrichum, Trifolium, Triodanus, Teucrium, Verbena, Veronicastrum, Vicea, Zizia), blood, and mud (Scott 1986, 2014; Tooker et al. 2002).

Reproductive Characteristics
Females lay eggs singly on host flowers, buds, stems, sometimes leaves (Scott 1986, 1992, 2006). Eggs hatch in about 5 days, L1 and L2 instars feed on leaf buds, undersides of leaves, may develop rapidly to L4 instar 10 days post egg-hatch, pupation 20 days post egg-hatch. Adults eclose (emerge from pupae) in 8 days. Larvae build no nest, skeletonize leaves, are regularly attended by ants (particularly Formica pilicornis), overwinter as nearly-mature (L4 instar?) larvae (Scott 1979; James and Nunnallee 2011). Males patrol throughout the day low to the ground near host plant (Scott 1975b, 1986).

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Citation for data on this website:
Eastern Tailed-Blue — Cupido comyntas.  Montana Field Guide.  .  Retrieved on , from