Pupal wing epithelial cells double-stained with SYBR Green I for nuclei and MitoTracker Orange for mitochondria. (a) The border region containing the M3 and CuA1 compartments. The prospective eyespot area is indicated by an arrow. The scale bar represents 400 μm. (b) High magnification. The scale bar represents 60 μm. (c) Further higher magnification. The cellular diameter is approximately 10 μm. Many mitochondria are observed as rod-like structures. The yellow dots are mitochondrial DNA. The scale bar represents 10 μm. Similar results have been previously published .