I start to see American Ladies in late April, here in western Wisconsin.  The first individuals I see are usually adult females laying eggs.  Most of the eggs and caterpillars I find are on Pussytoes (Antennaria neglecta and A. plantaginifolia).
Eggs on Pussytoes leaves
The young caterpillars pull a few leaves together with silk to form a nest. (The nests are easy to spot in clumps of Pussytoes.)
The caterpillars stay in their nests until they’re ready to make a chrysalis.
Chrysalis
Chrysalis ready to hatch
Newly hatched butterfly
After being released but before it flew away
Marcie O’Connor
Buffalo County, Wisconsin