The prepupal salivary glands of Drosophila melanogaster.

Evidence is presented in support of the concept that the larval salivary gland of Drosophila melanogaster continues to function as an important secretory organ throughout prepupal stages and after pupation. Just after puparium formation, and at other later periods, the glands appear to be in the process of disintegration, but each time they recover until after pupation. Nuclear blebbing occurs through the time of survival of the glands, but is shown not to involve transport of RNA out of the nucleus. Transport in and out of the nucleus is clearly rapid and in a steady state as compared to the massive and intermittent export of cytoplasmic substance into the lumen of the gland.