ˈboat-fly
[f. boat n.]
A species of water-bug (Notonecta glauca), whose body resembles a boat.
| 1753 Chambers Cycl. Supp., Boat-fly, a water-insect..he swims, says Moufet, on his back. 1860 Gosse Rom. Nat. Hist. 15 The merry little boatflies are frisking about, backs downwards, using their oar-like hind feet as paddles. |