| Eristalis tenax, Eristalis arbustorum, Bill Gates' flower fly|
Eristalis is a large genus of hoverflies, family Syrphidae, in the order Diptera. One of the more common species in the genus, Eristalis tenax is also known as the dronefly, because it bears a superficial resemblance to honeybee drones. Droneflies and their relatives are fairly common generalist pollinators, the larvae of which are aquatic, and breathe through a long, snorkel-like appendage, hence the common name rat-tailed maggots.
Eristalis is a large genus of around 99 species, and is subdivided into several subgenera and species groups (Eristalomyia, Eristalis, Eoseristalis etc.).