What is "eristalis"

Eristalis \E*ris"ta*lis\, n. [NL.] (Zo["o]l.) A genus of dipterous insects whose young (called rat-tailed larv[ae]) are remarkable for their long tapering tail, which spiracles at the tip, and for their ability to live in very impure and salt waters; -- also called drone 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.).