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Montana Field Guide

Montana Field Guides

Great Basin Wood Nymph - Cercyonis sthenele

Native Species

Global Rank: G5
State Rank: SU

Agency Status

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General Description
[From Ferris and Brown 1981; Scott 1986; Glassberg 2001; Guppy and Shepard 2001; Pyle 2002] Forewing 2.2-2.6 cm. Light to dark brown above, with two dark eyesponts on forewing (upper one larger) with or without yellow rings and pupils (eyespots larger on females); silvery brown underneath, ventral hindwing strongly two-toned and striated (dark inner part, pale outer third often frosted), two ventral forewing eyespots, usually fewer than six small ventral hindwing eyespots.

One flight; mostly late June to early August (mid-June to mid-July in the Coast Ranges)(Scott 1986); mainly July to August, but mid-May to mid-September across range (Glassberg 2001); late June to late September (Pyle 2002); mid-June to mid-September (James and Nunnallee 2011).

Diagnostic Characteristics
Best distinguished by the two large eyespots on the forewing, the rear eyespot smaller than the front one, easiest to see size difference on under forewing; outer portion of under hindwing lighter than inner half, with strong line separating the two areas.

Species Range
Montana Range Range Descriptions


Range Comments
Southern British Columbia south to extreme southern California, extreme northern Arizona and northwestern New Mexico, east to central Montana, western Wyoming, and western Colorado (Scott 1986; Glassberg 2001); to at least 1525 m in the Pacific Northwest (James and Nunnallee 2011). In Montana, found at lower elevations in the montane western third of the state (Kohler 1980; Stanford and Opler 1993). Uncommon to common (Glassberg 2001).

Observations in Montana Natural Heritage Program Database
Number of Observations: 7

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)


Lower-elevation arid-zone chaparral, moist canyons, juniper and oak woodlands, ponderosa pine and Douglas-fir woodlands, sagebrush-steppe, rangelands (Scott 1986; Guppy and Shepard 2001; Pyle 2002; James and Nunnallee 2011). Habitat in Montana not described.

Food Habits
Larval food plants are undetermined grasses. Festuca and Poa reported; raised in captivity on Setaria glauca (Ferris and Brown 1981; Guppy and Shepard 2001; Pyle 2002; James and Nunnallee 2011). Adults feed on flower nectar, including Achillea, Asclepias, Chrysothamnus, Cirsium, Eriodictyon, Melilotus, and Solidago (Pyle 2002; James and Nunnallee 2011; Scott 2014).

Reproductive Characteristics
Limited information. Females lay 100-150 eggs singly on host plant. Eggs hatch in about 5-7 days, L1 instars rest on host plant and enter diapause (overwinter) without feeding. In captivity, development from L1 to adult eclosion lasts 110 days; L1-L5 occupy 26, 10, 8, 12, and 22 days, respectively; pupal stage lasts 32 days before adults emerge (eclose). Larvae feed on grass at night, returned to base of host plant during day; no nests built. Pupate on host plant; adults live 5-10 days in wild (Emmel 1969; Scott 1986; Guppy and Shepard 2001; James and Nunnallee 2011).

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Citation for data on this website:
Great Basin Wood Nymph — Cercyonis sthenele.  Montana Field Guide.  .  Retrieved on , from