Phylogenetic relationships within the Drosophila sulfurigaster species-complex, which belongs to the D. nasuta subgroup, were investigated on the basis of chromosomal constitution and morphology. D. pulaua is thought to be the most ancestral species, from which D. s. sulfurigaster and D. s. bilimbata derived in one branch and D. s. albostrigata and D. s. neonasuta in another branch.