Moved from Giant Swallowtail. Found some larger caterpillars on Ptelea today and they were definitely glaucus. Will try to get them posted later.

We just assume that Papilio we find on Wafer Ash and Prickly Ash, our two local Citrus plants, are cresphontes, and the big ones we find certainly are. We think we took some small ones on Prickly ash. We'll see if we posted those images and provide a link for comparison.

Here's an 11 mm one and it does have a white posterior!

Guess we'll have to search for some small ones this year and see!

I look at it, and I see Papilio glaucus, but they are so similar at this age that I don't know if one can be certain. Usually (I thought always) P. cresphontes is pale at the end of the abdomen once past the first instar (even usually then). Usually the blue (sometimes white) spots are more obvious on P. glaucus (but they are in the same place on both). I have no idea if P. glaucus can use Ptelea; I would have said not, but could be wrong (I don't think there are any host records in Rutaceae nor Apiaceae for any Pterourus species).

I'm not saying this one is wrong, just pointing out some observations.