I came across a large, pretty fly yesterday afternoon:

It’s a Snail Parasitic Blowfly (Amenia), found on the east coast of Australia. It has an orange head with large brown eyes outlined in white — almost as if it’s wearing sunglasses. Its body is mostly black, with turquoise, green, and purple patches and white spots. The wings are transparent.

Unlike other blowflies, this one doesn’t lay eggs or maggots in dead flesh. Instead, it lays its live larvae onto the shells of snails. The larvae then feed off the snail. The adult flies feed on nectar, helping to pollinate flowers.

There are many different types of blowfly, not all of them as pretty as this one. Evidently the name “blowfly” comes from Shakespearean times: when flies laid eggs on meat and maggots emerged, the meat was called “fly blown”.