Caterpillar in NE PA

[krambo]

Found this guy on the side of my house in North East PA, 2 days ago. I am used to interesting cats in the area however this one throws me for a loop. I initially thought it was a Hackberry due to the tree near by however I do not think so.

Food source near by:

Hackberry
Wild Black Cherry
Walnut
Ash
Dogwood

Boxwood shrubs
Winterberry Holly shrub

He is now pupating, hanging upside down, typical of most butterfly caterpillars (think monarch).

Any help would be apreciated!

Attachments:

[bluemoth]

Looking at my book of butterfly caterpillars of the US I beleave you found a Red Spotted Purple larva ( limenitis arthemis ). The skin under the black horns on the larva is light tan not white as in the Viceroy larva.

[starlightcriminal]

Yep, that's it. They eat Prunus serotina in the south, one of the hosts you found nearby.

[krambo]

Awesome! You guys are great, thank you so much. While they are found in my area time to time, this is my first larva.