Olympia Marble
Euchloe olympia
Description 1 1/2-1 3/4" (38-44 mm). Chalk-white, with narrow, angular to sharply rounded wings; FW above has gray-marked tip, black-checked cell. Yellow-green marbling in discrete pattern on HW below, showing through to upperside. Most fresh individuals on prairies and fewer farther east show bright rosy wash on base of HW above and below.
Similar Species Creamy Marblewing has denser marbling on HW below, no rosy flush, and much heavier black marking at tip of FW above.
Life Cycle Caterpillar bright green, striped lengthwise with gray and yellow; feeds on buds and flowers of several kinds of rock cress (Arabis), hedge mustard (Sisymbrium officinale), and other mustards. Rosy purple chrysalis changes to gray-brown; overwinters.
Flight 1 brood; March-June.
Habitat Open woods and meadows in eastern portion of range; watercourses and nearby fields and bluffs, foothill ridges and open grasslands farther west, sandy flats and dunes in Great Lakes area.
Range SE. Alberta to S. Ontario southward to West Virginia, N. Texas east of Rockies.
Discussion The easternmost marblewing in America is also the most singular looking, especially with its rosy color when newly emerged. It seems to remain rather strictly within its range and is considered uncommon, although it occasionally wanders and at times can be fairly numerous locally. The number of adults on the wing fluctuates dramatically. This butterfly's anonymity is partly accounted for by its brief flight period early in the season and the excellent camouflage of its folded wings against yellow-green cresses.
Source
