Nomina Insecta Neartica
only lists 1 North American species, iole
Small, with elongated forewings. Upperside yellow with black markings, female with more extensive black than male. White form very rare. Underside of forewing with orange or yellow patch at base of wing and black spots at outer wing edge. Winter form has dusty green hindwing, summer form hindwing is pale yellow.
Resident in Guatemala north to peninsular Florida and the Southwest. Cannot survive cold winters, therefore every summer re-colonizes through the Great Plains to southeast Washington, southeast Idaho, Wyoming, and Minnesota.
Open, dry places including coastal flats, weedy fields, grasslands, road edges, meadows, and hillsides.
Low-growing plants in the aster family (Asteraceae) especially shepherd's needle (Bidens pilosa), Spanish Needles, (Bidens alba), sneezeweed (Helenium), fetid marigold (Dyssodia), and cultivated marigold (Tagetes).
Males patrol a few inches above the ground in low areas for females. Females lay eggs singly on leaves of host plant seedlings. Adults rest with wings closed and held perpendicular to the sun's rays to warm themselves.
This is North America's smallest sulphur (1)
"Butterflies of North America (Kaufman Focus Guides)" pp. 70-71 (1)
Glassberg, p.64, plate 8 (2)
has some great photos of pinned specimens.
Nature Photographer, Randy Emmit, also has some nice shots