Anomala innuba.
Size: approx. 9 mm. Photo: 08/15/12, 11 pm.

This Shining Leaf Chafers is Anomala innuba. The second reference reports that A. innuba exhibited bimodal flight activity with peak activity from late April to mid-May and early August to mid-September in Gainesville, Florida. In this large study, A. innuba, A. marginata, and A. undulata represented 13.5% (n = 5,964) of the total catch (N > 44,000). 
bug guide (this photo):
E. A. Buss, Florida Entomol. 83, 32 (2006):

Anomala undulata.
Size: approx. 10 mm. Photo: 04/08/12, 9 pm.

Anomala undulata belongs to the Shining Leaf Chafers. Adults are most often found March through May. 
bug guide (this photo):