Water Striders (Gerridae) are a predatory "true" bug. They are often seen zipping around over the surface of ponds, exploiting surface tension as a means of support.  You can learn more about them here and many other places on the Web.

The pictures featured in this gallery section were taken in late June, 2011, at a pool in a mountain stream. It was evidently the mating season.

All pictures taken with Nikon D7000 and Micro-Nikkor 105 mm VR, ISO 1000.