Mutant flies are incapable of free flight. Wing beat frequency is reduced to approximately one-half of the wild-type frequency during tethered flight. Time to mating of mutant males under noncompetitive conditions (single pair matings) is not significantly different from wild type. The average value for each courtship song component (sine song frequency, interpulse interval, intrapulse frequency and wing cycles per pulse) is within the wild-type range.