The digestive organs of Grylloblatta resemble those of the orthopteran suborder Ensifera but differ strikingly in the cuticle and epithelium lining the proventriculus, in which there are 12 similar longitudinal divisions characterized by rows of flexible, backwardly directed lamellae, in place of the six divisions of the Ensifera armed with columns of complex sclerotized teeth. The proventricular collum is much longer than in any of the Ensifera; the two gastric caeca of the latter are represented by a single bilobed sac; the malpighian vessels are fewer than 30 and are simply arranged; and the salivary glands are very compact, appearing like a single organ.As a main conclusion to this and the previous papers of this series the following views are advanced:(1) The Grylloblattaria, although cursorial, are the nearest relatives of the Ensifera, but differ from the latter group too widely to be included within it.(2) The saltatorial habit has been independently evolved in the Ensifera and Caelifera.A summary is given of the main views on the function of the proventriculus in mandibulate insects, particularly the orthopteroid forms. The proventriculus of Grylloblatta is believed to serve as a regulatory valve and also possibly as a propulsive organ for the movement of food along the digestive tract.