Butterfly Atlas Species Accounts

Butterfly Atlas data collected from 1986-1990

Tawny-edged Skipper

Polites themistocles

Named

Latreille,1824

Identification

Wingspan: 7/8 to 1 and 7/16." This species and the Crossline Skipper (P. origines) are similar. A useful preliminary character in separating the two is overall size with the Tawny-edged being typically smaller. Males of both species, and females of the present species show orange scaling along the leading edge of the forewing above and below. The hindwing below is brassy and only occasionally shows a faint crescent of light spots. Note that when viewed in the closed-wing (ventral) position the present species shows a strong contrast between the hindwing color and the "tawny-edge" of the forewing. Crossline males show less contrast here. A careful comparison of the stigmas in male themistocles and origines shows the former to be relatively chunky with a sinuous outline, while the latter is more slender and straight. Also note that themistocles shows a tiny, flag-like orange mark at the end of the stigma while the distal end of origines‘ stigma is often bordered by yellow scales. Flight times are also useful in separating the two species with Tawny-edged peaking in June and August while Crossline Skipper flies mainly in July.  Though superficially similar, the "jizz" (i.e. the overall impression created by the sum of their characteristics) of these two species is quite different and with experience they are readily distinguished on sight.

Distribution

Southern British Columbia east through southern Canada to Nova Scotia; southern Arizona east along Gulf Coast, though absent in most of Texas, to central Florida. Throughout New England except northernmost Maine.

Status in Massachusetts

A common to locally abundant species across the state including Cape Cod and Martha‘s Vineyard. While not recorded on Nantucket during the Atlas Period, historic records indicate that it occurred there once; it may still be present. Scudder (1889) states, "In New England . . . it is everywhere common." Maximum: "hundreds," 2 June 1985, Millis (Norfolk Co.).

Flight Period in Massachusetts

Two flight periods: generally from the fourth week in May through mid-July and from early August through early September. Outside dates: 25 May 1986, S. Hadley (Hampshire Co.), T. Fowler and 20 September 192, Norfolk (Norfolk Co.), B. Cassie.

Larval Food Plants

Mainly panic grasses (Panicum).

Adult Food Sources

These butterflies take nectar from a wide variety of sources and were found visiting two dozen species of flowering plants by atlas workers. Tawny-edged Skippers frequently use Red Clover and Cow Vetch which are normally readily available when they are on the wing.

Habitat

Fields, meadows, open hillsides, and vacant lots.

Life Cycle

EGG: Pale green; dome-shaped. OVIPOSITION: Eggs are laid singly on grasses. LARVA: Variable in color —yellowish, greenish or purplish-brown with one or two dark lateral lines; head dark with a white V on the front. CHRYSALIS: Overall grayish-white with green wing cases. OVERWINTERING STAGE: Chrysalis

Account Author

Richard K. Walton

Additional Information

Read more on this species at the North American Butterfly Association.