1. The time necessary for crawling 10 cm up an incline of 45° was found for earthworms, Lumbricus terrestris L., during test periods starting at 700, 1200 and 1900. 2. For 446 trials run in the morning, the average time was 17.19 seconds. For 475 tests done at midday, the average was 21.52 seconds, and for 475 trials run at 1900, it was 16.49 seconds. The differences between the averages for 700 and 1200 and for 1200 and 1900 are significant (p<0.001). 3. These results and differences in light-reaction times at 1200 and 1900 are compared.