Friday, August 6, 1999 — 9:30 am
Moraine Hills State Park, Illinois
This butterfly was flitting low over the path and the mowed grass along the edge of a large, weedy field on the Letherleaf Bog trail. It rarely ventured over the taller grass beyond the fringe of the trail. It landed frequently for short periods, but always with its wings tightly folded. Sometimes it perched on the ground, sometimes on weeds, and once on a purple clover flower.
The upperwings were pale yellow with a black border. There were a few yellow spots in the black area. The underwings were even paler, with a row of tiny, faint black spots submarginally, a pinking-rimmed white spot on the hindwing, and a black spot on the forewing. The black border on the upperwing could be seen through the wing.
After watching the Clouded Sulphur for a few minutes, an Orange Sulphur showed up. The two flitted around in tight circles and, a little later, perched side by side on a weed. When they were in flight near each other, the difference in color, pale yellow versus orange-yellow, was obvious.