Perfectly sized to work the minute central disk flowers of golden yarrow, a tiny insect -- perhaps a syrphid fly -- hovers a few millimeters from the plant, assessing the risk of continuing to feed.

The compound flower head of the golden yarrow (Eriophyllum confertiflorum) is about the size of a green pea (10mm), and the individual disk flowers at its center are about 1/5 as large (2mm).

From a run at Sage Ranch Park on May 28, 2007.

Related post: Bee Fly on Western Wallflower.