Abstract
As has been reported previously growth and proliferation during embryonic stage of the posterior silk gland could be described subdividing into the following three phases.
The first (blastokinesis 24 hours) or the latent phase when a number of free ribosomes exist in the cytoplasm, the second phase when rough ER proliferate rapidly, and the thired phase when fibroin is synthesized vigorously.
It was found that whorl structures and / or concentric lamellar structures of endoplasmic reticulum appear occacionally in the beginning of the third phase (blastokinesis 108 hours), develop rapidly and then disappear already at blastokinesis 120 hours (the stage of fibroin biosynthesis).
Those types of ER are probably formed by overproduction of rough ER and then transformed rapidly to vesicular or tubular ER in accordance with the start of fibroin biosynthesis.
