100 Hz remains upper limit of synchronous muscle contraction--an anomaly resolved.

Wootton and Newman introduced a problem when they showed, by high-speed cinematography, that a minute hemipteran insect, the whitefly Trialeurodes vaporariorum, achieves a wing-beat frequency of up to 181 Hz. 100 Hz had been regarded as the upper limit of contraction by myoneural synchrony, and whitefly flight muscle had been placed in the 'synchronous' category on structural grounds. The problem is resolved by evidence presented here, which reclassifies the power-producing flight muscles of whiteflies as 'asynchronous'.