The silkworm moth escapes from the pupal-protection case by utilizing cocoon-digesting enzymes. The rectal sac was examined in relation to the behaviour of the animal. Pupae and pharate adults were obtained from commercial races and were reared in the laboratory. The ball-shaped rectal sac, easily distinguishable within the abdomen of the silkworm, was found to contain two phased creamy fluid. The occurance and the shape of the organ and the usage of its fluid suggest its role in perforation of the cocoon.
MUTAF, BERİA FALAKALI and TURGAY, GAMZE (1999) "Some Morphological Features of the Rectal Sac of the Silkworm (Bombyx mori: Bombycidae)," Turkish Journal of Zoology: Vol. 23: No. 4, Article 11. Available at: https://journals.tubitak.gov.tr/zoology/vol23/iss4/11