insect visual primordium development biological_process GO:0001748 optic lobe and Bolwig's organ precursor development optic lobe placode development The process whose specific outcome is the progression of the optic placode over time, from its formation to the mature structure. During embryonic stage 12 the placode starts to invaginate, forming a pouch. Cells that will form Bolwig's organ segregate from the ventral lip of this pouch, remaining in the head epidermis. The remainder of the invagination loses contact with the outer surface and becomes the optic lobe. An example of this process is found in Drosophila melanogaster. optic placode development GO:0048049 anatomical structure development