substage of immediately preceded by late extended germ band stage developmental stage embryonic stage 10 embryonic stage 11 FlyBase_development_CV Temporal ordering number - 310. Stage 11 begins with the invagination of the tracheal placodes. Para-segmental furrow form and segment boundary furrows become deep folds. Within the head, gnathal protuberances become apparent. The end of this stage is signaled by the appearance of a distinct cleft at the posterior pole of the embryo, which becomes detached from the vitelline membrane. This marks the beginning of germ-band retraction. Duration at 25 degrees C: approximately 120 minutes (320-440 minutes after egg laying). FBdv:00005325 early extended germ band stage