Here we see several Monarch Caterpillars on milkweed plant leaves yesterday. (Special thanks are due to neighbor Sherry Streeter whose excellent milkweed plot welcomes this sometimes-troubled species and is the locus of the images here.)
This caterpillar and its larval siblings recently emerged from eggs attached to milkweed leaves by female Monarch Butterflies that may now be dead or dying. These caterpillars soon will pull hooded chrysalises over themselves, do a quick-change trick while hidden in their tombs, and climb out as our second generation of Monarch Butterflies (Danaus plexippus), the royalty of their kind (Leighton Archive images):
Monarchs produce four generations here during the warm months, three of which die after their Maine vacation. The fourth generation butterflies, born in September or October, are the special ones that migrate south to start the cycle again. (Brooklin, Maine)