Cloudless Sulphur
Phoebis sennae
Seven Springs area, north of Carefree, Maricopa Co., Arizona, USA. 5 Aug. 2018.
Pieridae -- White and Sulphur Butterfly Family
These large bright yellow butterflies mostly breed in Southeast Arizona and Mexico. After good summer rains they may disperse into the Sonoran Desert, occasionally in astounding numbers. Look for them August to October. The caterpillars feed on various members of the Ceasalpinioidae, a subfamily of the legumes that includes Desert Senna and Palo Verde. The males are solid yellow (sometimes with a greenish cast), but females have a narrow black border and additional small black markings.
These butterflies are frequent flower visitors. Seep Baccharis and Texas Bird of Paradise are favorites.