This little fly, seemed quite unassuming until I held it in the sunlight, and it sparkled iridescent, its thorax metallic green, its hairy abdomen gold. It is a male soldier fly (Stratiomyidae), a Dipteran as you can see from the club-like halteres in place of the hind wings. Its name is Chloromyia formosa, “the beautiful green fly”.

The book says the name soldier fly comes probably from the bright colours, like 18th century uniforms; the flies are not aggressive, but “often sluggish”.