Figure 1. A chain of follicles dissected from an ovariole from a pharate adult of Hyalophora cecropia. About four hours of developmental time separate neighboring follicles. This chain had been stained in vitro for 5 min with trypan blue, which binds to vitellogenic follicles while leaving post-vitellogenic follicles unstained. The largest staining follicle is 2.0 mm long.