| 0.5 |
Polar body formation |
| 1 |
Fertilization |
| 1-2 |
1st and 2nd mitotic divisions |
| 3 |
Formation of pole cells and primary yolk cells |
| 4 |
Peripheral migration of cleavage nuclei |
| 5 |
Pole cells outside the blastoderm |
| 6 |
Syncitial blastoderm |
| 8 |
Cellularization of blastoderm |
| 9 |
Germ band formation; secondary yolk cells |
| 11 |
Pole cell entry into the blastoderm |
| 12 |
Initiation of gastrulation; migration of presumptive mesodermal cells; elongation of the germ band |
| 14 |
Amnion and serosa formation |
| 15 |
Segmentation of the embryo begins; ventral nerve cord formation begins |
| 18 |
Labral lobe formation |
| 19 |
Anterior midgut-stomodaeal and posterior midgut-proctodaeal invaginations form |
| 25 |
Antennae, mandibles, and maxillae begin to form; anterior migration of the mouthparts begins |
| 30 |
Vitelline membrane present; germ band retraction begins; labial lobes appear |
| 35 |
Blastokinesis and dorsal closure begin; foregut differentiation and formation of the midgut begins; formation of the brain
and gonads initiates; labrum visible as distinct lobe
|
| 40 |
Differentiation of the suboesophageal ganglion and tracheal system starts |
| 45 |
Hindgut differentiation begins; formation of the retrocerebral complex and stomodaeal nervous system initiates |
| 50 |
Breakdown of the amnion and serosa; oenocytes and fat cells are formed; muscles of the head and mouthparts begin to form |
| 60 |
Differentiation of trunk musculature |
| 65 |
Heart formation |
| 75 |
Formation of the hatching spine begins |
| 96 |
Embryogenesis completed |
| aAfter Raminani and Cupp (1975, 1978).
|
| bThe timing of major embryonic developmental events is indicated in hours after egg laying at 25°C.
|
