The results of 13 month tappings (half-spiral cut) of 29 seedlings of rubber trees, approximately 25 years old, ore presented. From September 16, 1943 to March 31, 1944, the trees were tapped every other day; from Abril 1st, to September 30, 1944, every day. The change of the tapping system, from every other day to daily, caused a small decrease in the mean yield of the group, per tapping; this yield decrease was more pronounced and frequent in the high production plants. It must be remembered, however, that during the every day period of tapping the plants passed through regular hibernation. The study of the plants as a group presented the following results, respectively for every other doy and daily tapping systems: a) 10.3% of the plant population yielded 27.0 and 24.9% of the total latex production; b) 24.1% of the plant population yielded 49.5 and 45.0% of the total latex production; c) 48.3% of the plant population yielded 75.8 and 70.7% of the total latex production; d) 75.9% of the plant population yielded 92,7 and 90.4% of the total latex production.