Euphoria sepulcralis sepulcralis (Dark Flower Scarab).
Size: approx. 10 mm. Photo: 09/02/11, 10 am.

I found this beetle on a lantana flower. After moving the flower around to get a better photo, the beetle fell off and pretended to be dead. It is a Dark Flower Scarab (Euphoria sepulcralis sepulcralis). There are four recognized subspecies. The UF site refers to it as one of the "most frequently submitted" beetles. 

bug guide (these photos):