Worldwide distribution. They are also known as syrphid flies or flower flies; larvae feed on aphids mainly; adults are pollinators.
Oval, white eggs are laid singly near or among groups of aphids. The larvae are green, legless maggots.
Adults are typical flies with one pair of wings, large eyes, and they hover over flowers sucking up nectar.
Management: grow or encourage flowering plants, e.g., large daisies (white and yellow especially), and weeds, in and around gardens/fields. If >2 maggots in a colony of aphids that is enough to control them. Pesticides best avoided, or chose soap, white or horticultural oils, or neem that breaks down quickly.