Flight in Drosophila. II. Variations in stroke parameters and wing contour.

1. In tethered flight in a wind tunnel fruit-flies adjust lift and thrust by shifting the horizontal component of the lower extreme wing position. The upper extreme wing position is nearly constant. 2. Stroke angle and stroke plane are fully interdependent parameters. 3. Angle of attack varies along the length of the wing; no length-wise twisting occurs. 4. Angle of attack varies with flying speed; pitch is unchanged as speed is increased. 5. These characteristics suggest that the flight machinery of fruit-flies is considerably simpler than that of larger flying animals.