1 They use only their fore-wings for flight.

2 Immatures distinguished by white speckles on forewing and lack of white neck patch.

3 In flight forewing almost all white with black tip and trailing edge.

4 A rare transatlantic vagrant, with forewing bluer grey than wing, easily told by conspicuous white crescentic mark in front of eye.

5 Ciliatus forewing length and tilt, such as the caudate chicken.

6 Morphometric analysis of angles of forewing veins might be a useful tool for biodiversity studies of honeybees and other bees.

7 Upperwing has pale greyish-white primary bases and often pale rufous or yellowish-brown forewing, paler than dark grey flight-feathers.