1918.] NATURAL SCIENCES OF PHILADELPHIA. 89 



Whatever be the true homology of this portion of the gut, it is 

 clearly differentiated from the preceding and following divisions of 

 the alimentary canal by the presence of the three bands of thick 

 columnar epithelium. Histologically this columnar epithelium 

 appears similar to the longitudinal folds of columnar epithelium 

 found further caudad, in the rectal part of the hind-gut. The three 

 bands of columnar epithelium referred to in this, and the preceding 

 paragraph, extend from about section 35 or 40 to section 8 J (Fig. 6), 

 that is, through about the middle third or fourth of segment VII. 

 In Fig. 2, in addition to the parts already discussed, we see the 

 intima, i, basement membrane, 6, circular muscular coat, cm, and 

 the bands of longitudinal muscle, Im. There are six of the latter, 

 but they are not all visible in the photograph. They are located 

 outside the circular muscles, near the bases of the folds, 1, 3, 5, 7, 

 9, 11. The musculature of the posterior intestine of Mecistogaster 

 seems to be similar to that of the insects described by the authors 

 mentioned in this paper. 



Caudad to section 80 the gut narrows and the three bands of 

 columnar epithelium gradually assume again the appearance they 

 had cephalad to section 35. That is, the epithelium of these folds 

 becomes indistinguishable histologically from that of the other 

 folds. Indeed, in transverse section, the gut has much the same 

 appearance posterior to section 80 that it has anterior to section 35 

 (Fig. 1). This portion of the gut, from about section 80 to section 

 140 (Fig. 6), may correspond to the colon of some Orthoptera 

 (Minot, 1880, pp. 209, 217). Or (which is unlikely), if the portion 

 of the digestive tube immediately following this, instead of the one 

 immediately preceding, is homologous with the prerectal ampulla 

 of Anisopterous larvae (Sadones, pp. 280, 295), this is homologous 

 with the small intestine of Anisopterous larvse (Sadones, p. 279; 

 Tillyard, p. 131; Faussek, pp. 708, 709). 



At section 110 (Fig. 6), posterior part of segment VII, there are 

 six large folds (Nos. 2, 4, 6, 8, 10, 12), which practically fill the 

 lumen of the gut. 



At section 140 the above folds have decreased in size and the gut 

 has become pouched. This pouching increases greatly the diameter 

 of the lumen so that from sections 150 to 160 (Fig. 3 of sec. 150) it 

 is relatively very wide. The longitudinal epithelial folds project 

 caudad into these pouches for some distance. It may be that this 

 pouched portion of the intestine is homologous with the prerectal 

 ampulla of some Orthoptera (Bordas, 1898, pp. 48, 52) and Ani- 



