What is the function of digestive caeca in cockroach?

the alimentary canal of the cockroach is divided into 3 parts i.e. foregut, midgut and hindgut.the mouth opens to a small tubular pharynx leading to a narrow tubular passage called oesophagus. this opens to a sac like structure called crop which helps in storing food.the crop is followed by gizzard which helps in the function of grinding the food.a ring of 6-8 blind tubules called hepatic or gastric caecea which is present in the junction of foregut and midgut, which secretes digestive juice. at the junction of midgut and hindgut there are several thread like structures called malphigian tubules which helps in the removal of excretory product from haemolymph. the hind gut is differentiated into ileum, colon and rectum. the rectum at last opens out through anus.