segments,segmentation
A pattern that develops in the embryo of the fruit fl y, Drosophila melanogaster, which is defi ned by indentations giving the embryo the appearance of stacked disks with each disk representing a segment. Various structures of the adult such as legs, antennae, wings, and eyes develop from specifi c segments. Each segment consists of two halves: the A (anterior) compartment and the P (posterior) compartment.