Tachinid Fly

Last April (2012), I photographed this metallic-green fly basking in the sun on the West Pennine Moors.  I first thought that this was a green bottle, but I later learned that it was a Tachinid fly (Gymnocheta viridis), a true fly belonging to the family Thachinidae. 

Tachinids are parasitoids, their larvae feeding on the immature or adult stages of invertebrates such as butterflies, moths or beetles.