Identificaciones de platty12

We've been growing this milkweed patch for 5 years or so now, and it's finally about 5' across, and this is the first time we've found so many big caterpillars out here. Usually we spot a couple little ones that disappear and we blame the birds. Counted at least 10 tonight and most looked like they are probably about to pupate soon. Foraging on Asclepias fascicularis.