perhaps also Promethea Moth - Hodges#7764 (Callosamia promethea)

2015-5-8 www9 Patuxent Research Refuge, Anne Arundel County, MD
this cocoon was on the same bush, I don't know if it's of the same type as the other
When we went back the next day, the first cocoon was gone, but this one was sitll here, still occupied.
http://bugguide.net/node/view/1066361