A new herd of hatchlings?

 The large caterpillars all disappeared, but 2 days later 3 larger caterpillars and lots of babies appeared. Didn't see the eggs they hatched from . . .

 

Two days later they looked like this: 



 

April 30th -- One week later...

So, I thought these were baby black swallowtail caterpillars, but

after some research I discovered that they're actually a phase of ladybug larve!