280 Annals Entomological Society of America [Vol. Ill, 



The alimentary canal and especially the mid-intestine is 

 closely and firmly enclosed in columns of adipose tissue. Four 

 longitudinal lateral strands extend the full length of the larva 

 with shorter strands here and there. The adipose tissue and 

 Mali)ighian vessels form a perfect cushion about the canal and 

 in this way support it in the central part of the body cavity. 

 When the alimentary canal is dissected out the adipose tissue 

 adheres to it and severs its connection with the body wall, 

 and the respiratory and nervous systems. In living larvae 

 numerous fine tracheal branches, from the pair of dorsal longi- 

 tudinal tracheae, are seen to ramify the fat bodies and send 

 finer branches to the alimentary canal. The nervous connec- 

 tions with the adipose tissue and alimentary canal are much 

 finer and more difficult to discern than are the tracheal connec- 

 tions. Delicate cephalad directed fibers from the large dorsal 

 nerve, which extends caudad from the eighth abdominal gan- 

 glion, are seen to attach to the ileum just behind the Malpighian 

 vessels corresponding to suspensory nerves described by Com- 

 stock and Kellogg, '95, for Corydalis. These fine nervous 

 •connections from below with the tracheal connections from 

 above assist in supporting the alimentary canal. 



From surface view the hind intestine is distinctly divided 

 into ileum and colon, while the rectum is less easily made out 

 (Fig. 1). The ileum extends from the point of attachmentfof 

 the Malpighian vessels, opposite the anterior end of the sixth 

 abdominal segment, to the middle of the seventh segment where 

 it joins the much expanded colon. It is so much narrower than 

 the mid-intestine on the one hand and the colon on the other 

 that, in surface view, it stands out in sharp contrast with them. 

 The circular muscles of the ileum are strongly developed and 

 appear as a distinct transverse surface banding. The walls 

 are very thin and elastic. 



The diameter of the anterior end of the colon is twice that 

 of the ileum, while posteriorly it tapers to the rectum where it 

 is about equal that of the ileum. The walls of the colon are 

 very thick and but slightly elastic. The circular muscles are 

 strongly developed and are imbedded in pits in the epithelium. 



The rectum is quite short, extending from a point opposite 

 the anterior end of the eighth abdominal segment, where the 

 canal bends ventrad, to the anus. It is narrower than the colon 

 and the circular muscles are not imbedded in pits. Exteriorly 



