A fly dipped in gold
On a late-May morning in Pittsburgh, a tiny fly landed on a leaf in front of me and sat still, which is unusual enough among flies to be worth a look. The look was worth it: its back gleamed like polished brass in the morning sun. It was the kind of stillness that makes you check whether the insect is real, and the kind of color that makes you glad it is.
It was Chrysopilus thoracicus, the golden-backed snipe fly, a member of the family Rhagionidae in the order Diptera. The genus name means “golden-haired,” and the thorax of this species is a rich, metallic gold, which is where both the scientific and common names come from, and the name does not exaggerate. The dark abdomen and clear wings set the gold off nicely.
Snipe flies get their odd common name from their habit of perching on foliage and darting out to snatch small insects, a style of hunting that reminded early naturalists of the snipe, a bird that flushes suddenly from cover. The larvae live in soil and leaf litter, where they are small predators in their own right, and some snipe flies also visit flowers, taking small insects on the wing.
Most people swat flies without a second thought, but this one earns a second look. Gold, in Greek, is chrysos, and this fly wears it where it counts, on its back, and I count the sighting as one of the brighter moments of that May morning.
