Insect aerodynamics is drawing the attention of a number of researchers belonging to different disciplines with a view to understand its aerodynamic capabilities so as to revolutionise the aircraft technology. It is possible to understand, to some extent, the insect aerodynamics by experimentally determining the frequency of wing beat in its fethered state of flight by using flight sound technique and computing rate of mass flow, velocity, acceleration and mass of air induced in downward direction due to wing beat. This approach is found to give results that are in agreement with helicopter theory. Apart from this, the reacting force is expressed as a product of mass and acceleration of air in unequivocal terms rather than rate of mass flow and changing velocity.