Anatomy of the digestive organs ofSchizodactylus monstrosus(Drury) (Orthoptera)

Summary 1 The alimentary canal in Schizodactylus is almost tettigonioid. It is not very long, and is differentiated into the usual regions.2 The foregut is noteworthy because of its scanty armature. The crop is large, pyriform and more flattened dorsally. It possesses an additional propulsive device in the form of a group of cushions and an incomplete circular muscular band outside the cushions. The proventriculus has a well developed complex armature and mainly serves a triturating organ. The salivary glands are large and voluminous.3 The mesenteron is short and slightly curved. Two gastric caeca, one lying dorsally and the other ventrally, are quite large and almost round. Each caecal cavity is divided into five unequal chambers.4 The Malpighian tubules are arranged into six groups and placed equidistantly on the posterior margin of the mesenteron. Each group consists approximately of 39 to 42 tubules which open by a common ureter in the midgut just anterior to the pyloric sphincter.5 The proctodaeum is differentiated into ileum, colon and rectum. The ileum is slightly narrow and placed dorsally. The colon is ‘S’ shaped and lies ventrally below the ileum. The rectum is distinguished into an anterior wide rectal sac and a posterior small rectum proper. The rectal sac is further differentiated into an anterior and a posterior rectal sac, each bearing six transversely placed rectal papillae.6 A number of extrinsic muscles remain inserted on the rectal sac and the rectum proper, mainly for the purpose of defaecation.