Table 1.

Developmental landmarks used to time Drosophila embryonic development.

label	stage	description
0	cephalic furrow formation	ingression of cells around 30% embryo length, starting with cells on the lateral sides of the embryo
1	germband retraction	retraction of germband from dorsal side of embryo, with embryo transitioning from parasegmental to segmental division
2	head involution	internalization and rearrangements of head segments
3	midgut broadening	expansion of gut structures
4	muscle contractions	uncontrolled twitching of muscles
5	trachea filling	trachea system becoming filled with air
6	hatching	larvae exits from the embryonic egg shell