The surface modifications which follow the migration of the nuclei in the periplasm during stage 9 and 10 were studied in the earlyDrosophilaembryo by scanning electron microscopy. Anti‐tubulin immunofluorescence microscopy was also used to observe the changes in microtubule organization during the cap cycle 10. Cap formation occurs in three steps. First the caps enlarge and flatten, then a bilobed structure forms and finally the daughter caps become round and separate. The phenomenon of cap formation is related to the presence of actin and tubulin networks.