Fig. 1.

Structure of the digestive tract in Drosophila. The upper panel shows a schematic diagram of the body and digestive tract of Drosophila. The middle panel shows the general parts of the digestive tract, which is divided into three parts: foregut, midgut, and hindgut. The lower panel shows the fine structure of a portion of the midgut. The layer consisting of enterocytes, enteroendocrine cells, and intestinal stem cells is covered with muscle cells. There is a peritrophic matrix between the enterocytes and the microbes, which physically separates the enterocytes from the microbes.