406 Annals Entomological Society of America [Vol. IX. 



EXPLANATION OF PLATE. 



Figure L The alimentary canal of the larva of Haltica bimargitiata. 



b — urinary bladder. 



c — colon. 



cr — crop. 



i — ileum. 



nil — first division of the mid- intestine. 



in2 — second division of the mid-intestine. 



o — oesophagus. 



p— pharynx. 



r — rectum. 

 The walls of the alimentary canal are represented by dotted lines. 

 The course of the four Malpighian vessels of the first series is shown by wavy 

 lines. 



The course of the two Malpighian vessels of the second series is shown by solid 

 lines. 



Figure 2. Diagrammatic cross section of the colon showing the Malpighian 

 vessels migrating around the longitudinal muscles, 

 i — intima. 

 e — epithelium, 

 cm — circular muscle layer. 

 Im — longitudinal muscle fibres, 

 mv — malpighian vessels associated with the colon, 

 pe — peritoneal envelope. 



Figure .3. Diagrammatic cross section of the colon showing the typical 

 alternation of Malpighian vessels and longitudinal muscles. 

 i — intima. 

 e — epithelium, 

 cm — circular muscle layer. 

 Im — longitudinal muscle fibres, 

 mv — malpighian vessels associated with the colon, 

 pe — peritoneal envelope. 



Figure 4. Diagram showing the ramification of one of the Malpighian trunks 

 in the wall of the colon. 

 C — colon. 

 R — rectum. 



Figure 5. Scheme showing very diagrammatically the insertion and relation 

 of the_two series of Malpighian vessels. 

 C — colon. 

 I — ileum. 

 M — mid-intestine. 

 R — rectum. 



