100 



DIGESTIVE APPARATUS OF INSECTS. 



we see amongst the higher animals a connection between the 

 nature of the food and the development which this canal acquires, 

 so among the Carnivorous Insects it is generally very short ; 

 whilst among Insects which are supported on Vegetable sub- 

 stances, it is usually very long. 

 The food which enters it, is at 

 first moistened with the sa- 

 liva ; the apparatus which 

 secretes this liquid consists of 

 a certain number of floating 

 tubes, terminated sometimes by 

 small follicles or sacs, and 

 communicating with the pha- 

 rynx by their excretory canals. 

 A multitude of villi, with 

 which the digestive or chylific 

 stomach is generally furnished, 

 appear to serve for the secre- 

 tion of a gastric juice ; and it 

 is also into this cavity, that the 

 bile is poured. There does not 

 exist any liver, properly speak- 

 ing, among Insects; but] this 

 organ is replaced by long and 

 delicate tubes (^), which float 

 in the interior of the abdomen, 

 and open high up in the chylific 

 stomach. (Similar vessels, open- 

 ing lower down, take the place 

 also of the urinary glands ; for 

 uric acid has been found to be 

 secreted in them.) By one of 

 their extremities, the biliary 

 vessels always open into the 

 chylific stomach ; and the other 

 extremity is sometimes free, 

 but sometimes fixed to the intestine, either near the first opening 



324. DIGESTIVE APPARATUS OF BEETLE ; a, 

 pharynx ; 6, oesophagus ; c, crop ; d, giz- 

 zard ; e, chylific stomach ; /, small intes- 

 tine ; g, rectum ; h, biliary vessels. 



