TABLE OF CONTENTS 



b. The fore-intestine 



The layers of the fore-intestine 



The intima 



The epitheHum 



The basement membrane 



The longitudinal muscles 



The circular muscles 



The peritoneal membrane 



The regions of the fore-intestine 



The pharynx 



The oesophagus 



The crop 



The proventriculus 



The oesophageal valve 



c. The mid-intestine 



The layers of the mid-intestine 



The epithelium 



The peritrophic membrane 



d. The hind-intestine 



The layers of the hind-intestine 



The regions of the hind-intestine 



The Malpighian vessels 



The Malpighian vessels as silk-glands 



The caecum 



The anus 



4. THE RESPIRATORY SYSTEM 



a. The open or holopneustic type of respiratory organs 



1. The spiracles 



The position of the spiracles 



The number of spiracles 



Terms indicating the distribution of the spiracles 



The structure of spiracles 



The closing apparatus of the tracheas 



2. The tracheae 



The structure of the tracheae 



J. The tracheoles 



4. The air-sacs 



5. Modifications of the open type of respiratory organs. 

 h. The closed or apneustic type of respiratory organs 



1. The Tracheal gills 



2. Respiration of parasites 



3. The blood-gills 



