抄録
1. By using 83 III-IV tr. and 126 III-V tr. an evidence for the presence of inert regions in the autosomes of D. virilis has been given.
2. The discrepancy found between the length of the oogonial chromosomes and that of the salivary gland chromosomes in 202 III-V tr. gives the evidence that nearly the half of each autosome is made up of inert material.
3. The so-called β-heterochromatin, which is found in the proximal ends of the salivary chromosomes, does not correspond to the inert regions.
4. The point of the spindle fiber attachment of the fourth chromosome is found at the other end of the plexus locus. The point of the spindle fiber attachment of the fifth chromosomes is found to the right of peach.
