1922] Branch: Internal Anatomy of Trichoptera 273 



EXPLANATION OF PLATES. 



PLATE XIV. 



Fig. 1. Central nervous system of Limnophilus indivisus and larval reproductive 



organs. 

 Fig. 2. Central nervous system of Phryganea interrnpta and larval reproductive 



organs gdl=gonad from the ental lateral aspect. gd2 = gonad 



frequently found and assumed to be the ovarian gonad. 

 Fig. 3. Central nervous system of Hydropsychodes analis and anal region with 



blood gills protruding from anus. 



Fig. 4. Dorsal aspect of the supracesophageal ganglia of Limnophilus indivisus. 

 Fig. 5. Lateral aspect of the supracesophageal and subcesophageal ganglia of 



Limnophilus indivisus. 



Fig. 6. Ventral aspect of subcesophageal ganglion of Limnophilus indivisus. 



Fig. 7. Transverse section through the ovary of H. analis. 



Fig. 8. Ventral aspect of the circulatory system of L. indivisus. 



PLATE XV. 



Fig. 1. Lateral aspect of the alimentary canal of Limnophilus indivisus. 

 Fig. 2. Oesophageal valve of Limnophilus indivisus. The portion of the canal 



containing the valve has been slit longitudinally and the valve laid 



open. 



Fig. 3. A transverse cut back of the oesophageal valve. 

 Fig. 4. Diagram to show the relative position of the Malpighian tubules at the 



division between mesenteron and hind intestine. 



Fig. 5. Transverse cut through the rectal valve at a level with 5 in Fig. 1. 

 Fig. 6. Lateral section through the oesophageal valve. The cephalic end of the 



valve is toward the bottom of the page. 



Fig. 7. Lateral aspect of the alimentary canal of Hydropsychodes analis. 

 Fig. 8. Caudal aspect of anus of Hydropsychodes analis. 

 Fig. 9. Dorsal aspect of the anus of Hydropsychodes analis. 

 Fig. 10. Longitudinal section through the division point between mesenteron 



and hind intestine showing a valve, caudad of the Malpighian tubules; 



and the folded digestive epithelium of the mesenteron. 

 Fig. 11. Ventral aspect of the alimentary canal of Phryganea interrupta, only the 



ventral pair of tubules are figured. 



PLATE XVI. 



Fig. A. Diagram of the hind intestine of Hydropsychodes analis, with the levels at 



which the figures 1-6 are taken, indicated. 

 Fig. 1. Cross-section through the hind intestine at a point where a semi-rectal 



valve is formed by the invaginated folds of the intestinal wall. 

 Fig. 2. Cross section taken at level No. 2, showing the glandular structure of 



the large intestine. 

 Fig. 3. Cross section at level Xo. 3, showing the six folds of the small intestine 



with the cubical cell in the wall and the ental layer of circular 



muscles with the six pairs of longitudinal muscles. 

 Fig. 4. Cross section at level No. 4. showing the ectal row of circular muscles 



in addition to the condition in Fig. 3. 

 Fig. 5. Cross section at level No. 5, showing the beginning of the columnar 



epithelial cells and the breaking up of the six pairs of longitudinal 



muscles into a layer of smaller longitudinal muscles. 



