Montana Field Guide

[From Ferris and Brown 1981; Scott 1986; Layberry et al. 1998; Opler and Wright 1999; Glassberg 2001] Forewing 1.5-1.6 cm (males), 1.8 cm (females). Bright yellow-orange, fringes usually orange. Uppersurface with black outer margins, veins with at least some black, sometimes through submarginal to median region, forewing with black bar at end of discal cell and females with a larger elongate black patch at wing base; undersurface of hindwings unmarked yellow-orange.

One flight, late June through July northward and in Colorado; several flights southward, February to October in Florida, April to October in Texas (Scott 1986). May to October in south, mid-June through July in north (Glassberg 2001). Mid-July to mid-August in Canada (Layberry et al. 1998). Late June through July in the Rocky Mountain states (Ferris and Brown 1981), late June to late July in Colorado (Scott and Scott 1978), late June through July in North Dakota (Mccabe and Post 1976).

Best determined by a combination of orange-tan fringes, black margins and black wing veins on bright yellow orange uppersurface, unmarked yellow-orange undersurface.

Non-migratory.

Wet brushy fields, wet meadows, marshes, prairies, foothills, open woodlands (Ferris and Brown 1981; Scott 1986; Layberry et al. 1998; Opler and Wright 1999; Glassberg 2001); favoring less disturbed prairie over fields and barrens (Nelson 2007; Swengel and Swengel 2015), sometimes present in low numbers in marshes dominated by exotic sedge (Catlin and Kostiuk 2014). Habitat in Montana not described but probably similar.

Larval food plants are grasses, including Andropogon(?), Bromus, Erianthus, and Panicum (Ferris and Brown 1981; Scott 1986, 1992, 2006; Layberry et al. 1998). Adults feed on flower nectar (including Asclepias, Carduus, Cephalanthus, Cirsium, Echinacea, Heterotheca, Medicago, Monarda, Prunella, Silphium, Teucrium, Verbena, Vicea) and mud (Tooker et al. 2002; Scott 2014).

Limited information. Females lay eggs singly on host plant leaves. Larvae eat host plant leaves, live in nest of rolled or silk-tied grass leaves, overwinter (diapause) as half-grown (L3-L4 instar?) larvae, emerge in spring and pupate in rolled leaf nest on host plant; adults eclose (emerge) from pupae in 12-13 days in captivity (Scott 1979, 1986, 1992). Males perch throughout the day in grassy swales and gulches awaiting passing females (Scott 1975b, 1986).