Svastra sp. (Long-Horned Bee (nonspec.)).
Size: approx. 10-15 mm. Photo: 08/28/11, 7 pm.

We have many of these Long-Horned Bees (Svastra sp.) flying around our petunias and lantanas. Although they have been there for weeks, it took me a long time to shoot a good photo. They are pretty fast and only stop for seconds while taking nectar. This genus has 14 species in our area, which are all robust and hairy. 

bug guide (these photos):