Figure 3. Section of a vitellogenic Hyalophora follicle that had been stained with Azure-B to reveal the distribution of RNA. Cytoplasm is deeply stained. Three giant, folded nurse cell nuclei are at the top of the section. A flattened epithelium of follicle cells covers the nurse cells while the oocyte is covered by taller, columnar-shaped cells. The oocyte is close-packed with non-staining yolk particles. An RNA-rich delta of cytoplasm lies close to the nurse cells at its anterior pole and a lightly staining cortex underlies its surface (Reprinted with permission from Pollack and Telfer 1969 Journal of Experimental Zoology 190:1–24.)