[The gonotrophic cycle and the daily rhythm of bites of Anopheles gambiae (Giles) 1902 and Anopheles nili (Theobald), 1904].

The authors have elaborated a formula to calculate the average number of times an anopheline parous female bites in one day ("L") according to its gonotrophic cycle and more specially to its behaviour before and after oviposition (parameters "alpha" and "A". The formula was applied to Anopheles gambiae observed at Djoumouna village (L = 0.40) and to Anopheles nili observed at M'Pola village (L = 0.30). The value obtained has then to be multiplied by the anthropophilic index to obtain the "a" parameter of MacDonald (1957) when studying malaria transmission in a village. On the other hand such a formula allowed a better evaluation of biting frequency of a vector, thus of risks of transmission of diseases, according to the respective situation of human houses and water storages. An important point which ahs to be born in mind when planning artificial permanent reservoirs.