Abstract: The present paper reports on two forms of Anopheles (Cellia) minimus collected from-various parts of Hainan Island during 1964 and 1981-1982. Based upon a detailed study of the morphological characteristics of adult, larval and pupal stages, as well as of behaviors of susceptibility to DDT, the author is of the opinion that there are at the present two forms of Anopheles (Cellia) minimus, namely, A and B. The main characteristics of these two forms are given below.An. (C.) minimus form APalpi with apical one-third in dark ring, rarelyflavescent ring, or not three times hind bands. Firtt branch (vein m1+2) of 4th longitudinal veinwith 1-2 pale scales or rarely entirely dark. Single cone, anterior view of cirbarial armaturewith filament and bifurcated at the apex.Mental plate with 7 rarely 9 teeth in the larval stages.An. (C.) minimus form BPalpi with apical one-third in flavescent ring,rarely dark ring, or not three times hind bands. First branch (vein m1+2) of 4th longitudinal veinentirely dark. Single cone, anterior view of cirbarial armature,filament, narrow, without the fimbriated ends.or lateral spicules, and not bifurcated at the apex. Mental plate with 9 or 11 teeth in the larval stages. Based on behavior studies in the 50s, it was proved-that Are. (C.) minvmus was one of the chief malaria vectors in the mountain regions of Hainan Island and frequented human dwellings more than cattle sheds during the day, and this species preferred human blood. After repeated residual house sprayings with DDT in 1956, the density decreased sharply. The author designates this form as An. (C.) minimus form A.In recent years, observations made during the period May-July 1981 and March-April 1982 in Zhangsha and Huangnigou regions of Hainan Island showed that An. (C.) minimus could be excited by and escaped DDT spraying and fed chiefly on cattle, resting no more inside houses in the south-western part of Hainan Island. The author designates this form as An. (C.) minimus form B, which is a peri-wild species there.