Content 



CHAP. 



INTRODUCTION 



I THE INTEGUMENT 



Composition of the cuticle. The epicuticle. Surface 

 forces and the insect cuticle. The moulting, formation and 

 pigmentation of the cuticle. The mechanism of moulting 

 and hatching. Metallic colours of the cuticle 



II RESPIRATION 12 



The tracheae and tracheoles. The diffusion theory of 

 insect respiration. Function of the spiracles. Ventilation 

 of the tracheal system. The regulation of respiration. 

 Regulation of tracheal supply. Respiration of aquatic in- 

 sects. Respiration of parasites 



III THE CIRCULATORY SYSTEM AND ASSOCIATED 



TISSUES 27 



Mechanism of the circulation. Control of the heart- 

 beat. Composition of the blood. Cytology of the blood. 

 Functions of the blood. Organs and tissues associated with 

 the blood 



IV DIGESTION 



The alimentary canal. Proventriculus. Peritrophic mem- 

 brane. Salivary glands. Secretion. Reaction of the gut. 

 Digestive enzymes. Symbionts in digestion. Absorption. 

 The faeces 



V EXCRETION 



Excretion of dyes. Nephrocytes. Urate cells. Pigments. 

 Verson's glands. Malpighian tubes and the urine. Excre- 

 tion in Rhodnius. Excretion in other insects. Excretion in 

 aquatic insects. Regulation of osmotic pressure and ionic 

 composition of the haemolymph. Accessory functions of 

 the Malpighian tubes 



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