METAPHASE KARYOTYPES OF ANOPHELES OF THAILAND AND SOUTHEAST-ASIA .4. THE BARBIROSTRIS AND UMBROSUS SPECIES GROUPS, SUBGENUS ANOPHELES (DIPTERA, CULICIDAE)

Metaphase karyotypes of 2 and 3 species of the Umbrosus and the Barbir ostris Groups, respectively, of the subgenus Anopheles occurring in Th ailand and Indonesia show inter- and intraspecific differences with re spect to the amount and distribution of constitutive heterochromatin i n the sex chromosomes and/or autosomes. Four forms of metaphase karyot ypes have been recognized in the wild samples of Anopheles barbirostri s based on differences in size and shape of X and Y chromosomes. It is not known whether forms A, B, and C of the metaphase karyotype of An. barbirostris found in Thailand represent inter- or intraspecific diff erences. However, form D, which occurs only in Indonesia, may represen t a mitotic karyotype of a distinct species closely related to An. bar birostris. Anopheles campestris and An. barbumbrosus are each readily separated from An. barbirostris by mitotic chromosomes. Anopheles umbr osus and An. letifer of the Umbrosus Group also exhibit heterochromati n variation in the X chromosomes. These 2 species can be readily disti nguished by the gross morphology of mitotic karyotypes, particularly t he X and Y chromosomes.