14 



INTRODUCTION. 



general idea of the digestive apparatus of an insect, 

 the various organs of which, of course, differ according 

 to the habits of the orders. 



The intestinal canal 

 lies in the median line 

 of the body, and runs 

 from one extremity to 

 the other ; it is formed 

 of three membranes, 

 and commences be- 

 hind the mouth in 

 an oesophagus, termi- 

 nating posteriorily in 

 a widened cavity 

 (cloaca), which also 

 receives the internal 

 generative organs ; 

 the oesophagus leads 

 into the first stomach 

 or crop, from thence, 

 in mandihulate in- 

 sects, into a second 

 stomach, which from 

 its beingsupplied with 

 horny plates to bruise 

 the food has been 

 called the gizzard; 

 this leads into the true 

 stomach, where the process of chylification takes place ; 

 the whole surface of this stomach is often plentifully 

 supplied with glandular bodies called villi, which are 

 supposed to secrete a gastric juice ; a number of very 



Digestive Apparatus of a Beetle. 



B, CEsophas^us. c, Crop, d, Gizard. e, Stomach. 



F and G, Small and large intestine. H, Anus. 



I, Biliary \ essels. k, Secreter}- organs. 



