Studies on the alimentary canal of the larva of Orthaga exvinacea Hampson (Lepidoptera: Pyralidae)

Histomorphological studies on the alimentary canal of sixth instar larva of Orthaga exvinacea Hampson at Oh development were carried out. The digestive tract can be differentiated into the foregut, midgut and hindgut. The foregut can be divided into buccal cavity, pharynx, oesophagus and crop. The midgut is the largest portion of the alimentary canal. The hindgut can be divided into five general regions, viz., the ileum, pylorus, colon, posterior sphincter regions, and the rectum. Slightly behind the junction between the midgut and hindgut there are six Malpighian tubules. Histologically the wall of the foregut is composed of peritoneum, muscle layers, basement membrane, epithelium and intima. The epithelium is composed of cuboidal and squamous.cells. The wall of the midgut is composed of muscle layers, a basement membrane and the epithelium. The epithelium is composed of two lypes of cells, viz., columnar cells and regenerative cells. The wall of the hindgut consists of the musculature, epithelium and the intima.