This genus includes 11 North American species. They are multivoltine. Larvae are predators of both free-living and gall-forming
aphids (Vockeroth 1992).
They have robust body with shining scutellum. This is the only genus in tribe Syrphini has long hairs on the upper surface of the lower lobe
of the calypter. Their abdominal tergite 2 has pair of yellow spots and tergites 3 and 4 have entire or divided bright yellow bands (Vockeroth 1992).
