Chloropid Fly
Thaumatomyia sp.
Near Sycamore Creek, Mazatzal Mts., Maricopa Co., Arizona, USA. 22 May 2016. Alighted on exposed vegetation.
Chloropidae -- Grass Fly Family
There are many species belonging to this genus of small flies. At least some species are predators of aphids in the larval stage. As adults they may visit flowers for nectar. The scutellum, a body structure, just behind the thorax is prominent and glossy (looks like a solid yellow half-disc in this photo).