How do flies land on the ceiling?

When flies land on the ceiling, do they flip or barrel-roll?

• Flies

• Answer:

  The leading theory for years was that the flies did a half barrel roll sideways a la the Blue Angels just before landing. This idea was shot down in 1958 whenNatural History magazine published photos showing that in fact flies do a sort of backward somersault. On approaching the ceiling, and while still flying right side up, flies extend their forelegs over their heads till they can grab a landing spot with the suction cups in their feet. Their momentum then enables them to swing their hind legs up, like a gymnast on a trapeze. --Cecil Adams, The Straight Dope, 1990 http://www.straightdope.com/columns/read/1074/how-does-a-fly-land-upside-down-on-the-ceiling