31.   The classic example, called the butterfly effect, asks whether a butterfly flapping its wings in Brazil could cause a tornado in Texas.

32.   The male flew on top of the female, and flapped his wings while the female clung to a branch.

33.   The paper shook in her hands like the mythical butterfly flapping its wings in South America, sending a shudder in the air that eventually becomes a hurricane.

34.   The secret of flapping insect wings, Ellington discovered, is that they are always on the edge of stalling, the point of maximum lift.

35.   They dry it out by flapping their wings, then seal off the cell with more wax.

36.   Using rubber-band propulsion to flap its wings, the bird swooped and glided over a crowd and left Schylling enthralled.

37.   When vultures take off, they flap their wings vigorously.

38.   When your friend suggests that hummingbirds flap their wings several hundred beats per second, he or she may be referring to hummingbird courtship flights.

39.   As is tradition, the Hawk constantly flaps its wings during every game.

40.   Both the usual small bats and their large cousins actually flap their wings to propel them in true flight.