438 



THE INVERTEBRATA 



Fig. 306. Diagram of a longitudinal section through the gut of Rhodnius 

 prolixus to show the entrance of Malpighian tubules. Amp. ampulla in 

 wall of hind gut, the long cells of which project into the rectum and with- 

 draw water from the excretory matter ; Mg. mid gut ; Mt.D. distal part of 

 Malpighian tubule at which place water and excretory matter enter the tube; 

 Mt.P. proximal part of Malpighian tubule from which water is returned to 

 the body cavity, leaving the excretory material in a granular state ; Rg. rectal 

 gland in wall of rectum. Modified after Wigglesworth. 



Fig- 307- Transverse section through dorsal part of the abdomen of Apis 

 mellifica to show attachment of heart to the body wall and to the diaphragm 

 by the alary muscles (al.m.). After Snodgrass. (The insertion of the alary 

 muscles in the tergum is not shown.) dg. diaphragm ;/.6. fat body; h. heart; 

 mg. mid gut; mt. Malpighian tubule; tra. trachea. 



