This is a single aphid (if it is an aphid; I don't see cornicles) on a tiny Lady's mantle flower—the flower can't be more than 5 mm in diameter. Yes, my new lens has arrived! It's a Raynox DCR-250 Super Macro Conversion Lens which does (as advertised) snap on to my Canon PowerShot SX10 IS camera. Today was very hot, bright and breezy, so the plants were waving around a bit and the bugs were in high gear themselves, but I had to take it out for a spin. I don't even really know how to use it yet, so I set up shop in a few sheltered areas of the yard and waited, and clicked clicked clicked. Crikey! It's just like they say: this lens adds additional superpowers to the camera, but it's really hard to get the focus right.
Here are some ants on my favourite spirea aphid colony. These are regular black ants, not some kind of enormous mutants. A single one (note the drop of honeydew shining in the sun opposite the ant):
Then there was some kind of dustup, and some of the ants got excited and started squabbling over the best aphids: