AbstractDrosophila nasuta species subgroup , belonging to Drosophila immigrans species group , consists of 14 closely related taxa in various levels of the speciation process. This subgroup exhibits much evolutionary idiosyncrasies which attract great interest in the study of speciation mechanism. However , extensive studies on morphometric , reproductive isolation , chromosomal , allozyme variation , mtDNA RFL P , and courtship song characteristics have failed to produce a coherent phylogenetic tree for this subgroup. This paper reviews the available data on the phylogeny of this subgroup , and some ideas for future research are proposed.