40 Drosophila species were kept under a light‐dark cycle of 12/12 hrs, at constant temperature and humidity. Locomotor activity was recorded using a method based on the measurement of variations in capacitance. The circadian patterns of the species tested differed with respect to number and phase of maxima and to the occurrence of a resting period in the middle of the light phase. The resting period, which is usually regarded as an adaptation to an arid climate, was also observed in several boreal species.