THE EGGSHELL OF DROSOPHILA-MELANOGASTER .8. MORPHOGENESIS OF THE WAX LAYER DURING OOGENESIS

Utilizing freeze-fracturing and conventional electron microscopy metho ds, we have studied the details of morphogenesis and construction of t he wax layer envelope from Oregon R and mutants of Drosophila melanoga ster eggs during oogenesis. The wax layer is synthesized and secreted by the follicular cells in the form of lipid vesicles during stage 10b . During secretion (stages 10b, 11 and 12) the lipid vesicles are accu mulated on the vitelline membrane surface and become fiat. At the late stages of choriogenisis (stages 13, 14) the lipid vesicles are compre ssed tightly between the vitelline membrane and the other already cons tructed eggshell layers, so the wax layer becomes very thin and is har dly seen in cross-fractured views.