The adult fly that emerges from the pupa is harmless. It looks somewhat like a drone honey bee, and likely gains some degree of protection from this resemblance to a stinging insect. The adults are called drone flies because of this resemblance. In its natural habitat, "E. tenax" is more of a curiosity than a problem. Like other hover flies, they are common visitors to flowers, especially in late summer and autumn, and can be significant pollinators. They often feed on the flowers of carrot and fennel.