Giant Ichneumon wasp (Megarhyssa_macrurus, Linneaus 1771) ovipositing.
10th of August 2013, Georgia State Botanical Garden, Athens, GA.
3:47 pm.

You can watch the entire behavior at Nature Documentaries:

http://naturedocumentaries.org/3843/giant-ichneumon-megarhyssa-macrurus-ovipositing/