The Collaborative International Dictionary
drone fly
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.
Usage examples of "drone fly".
But here they were just one of a varit insects, like the butterflies flicking their bright colors in a qu dance across the tops of the fescue, and the harmless drone fly resembled a stinging honeybee, hovering over a buttercup.