Are you sure you don't have any Parsley, Dill or Rue for them to use? On occasion, I do away with some butterfly eggs because there's not enough host plants, but I don't usually eliminate butterfly caterpillars unless they're really sick or something. Right now, I'm hoping no more Common Buckeyes lay eggs on what's left of the small Agalinis plants because there's still caterpillars that need what little foliage is left. I've never been able to spot the eggs for that species. Guess they must be really small or something.
