Metaphase karyotypes of eight species of the Neocellia Series (excluding the Maculatus Complex) showed inter- and intraspecific variation in the sex chromosomes and in the centromeric region of the autosomes based on the amount and distribution of heterochromatin. Anopheles jamesii Theobald and An. karwari (James) exhibited two and three forms, respectively, of metaphase karyotypes based on the different size and shape of the X and Y chromosomes. Anopheles annularis Van der Wulp, An. pseudojamesi Strickland and Choudhury, and An. philippinensis Ludlow also showed heterochromatin variation in the sex chromosomes. These kinds of sex chromosomes variations have not been observed in limited samples of An. stephensi Liston, An. nivipes (Theobald), and An. splendidus Koidzumi. Two groups of X chromosomes have been recognized based on the amount of centromeric heterochromatin in the euchromatic arm. Anopheles karwari, An. annularis, An. jamesii, An. pseudojamesi, and An. stephensi form one group, while group two includes An. nivipes and An. splendidus. Anopheles philippinensis has both kinds of X chromosomes, which may reflect the common ancestral karyotype of the species in this series.