A total of 227 iso-female lines of Drosophila immigrans collected at three populations near Matsue were investigated to make the standard photo-maps of the salivary gland chromosomes and to analyze the pattern of the chromosomal polymorphism of this species in this district.
Some characteristic descriptions of each chromosome were given.
Three types of chromosomal inversions were detected in this study and two of them were identical to Brncic's inversions A and B found in the Chilean populations of D. immigrans.
The mean frequency of heterozygous inversion was very low and was 0.053 per larva.