Synchlora frondaria - Hodges#7059
(Southern Emerald Moth).
Size: approx. 15-20 mm. Photo: 08/30/11, 10 pm.

This green moth is a Southern Emerald Moth (Synchlora frondaria). It came to the light of a window. Its larvae are very interesting twig mimics. They are highly variable as they decorate themselves with plant material. The genus has 12 species north of Mexico. The small photo shows a different example that I found on 3/26/16. 

bug guide (this photo):
Canfield et al. Ecol. Entomol., 34, 412, 2009: