10 



THE INSECT WOKLD. 



when one exists, that the food, separated by the masticatory 

 organs of the mouth, undergoes another and more complete 

 grinding. Its structure is suited to its office. It is, in fact, very 

 muscular, often half cartilaginous, and strongly contractile. Its 

 interior walls are provided with a grinding apparatus, which 

 varies according to the species, and consists of teeth, plates, spines, 

 and notches, which convert the food into pulp. It only exists 

 among insects which live on solid matters, hard vegetables, small 

 animals, tough skin, &c. This apparatus is absent in sucking 



insects and those which live on 

 soft substances, such as the pollen 

 of flowers, &c. 



The chylific ventricle is never 

 absent; it is the organ which 

 performs the principal part in 

 the act of digestion. 



Two kinds of appendages be- 

 long to the chylific ventricle, 

 but only in certain families. The 

 first are papillae, in the form of 

 the fingers of a glove, which 

 bristle over the exterior of this 

 organ, and in which it is believed 

 that the food begins to be con- 

 verted into chyle. The second 

 are caeca, and larger and less 

 numerous. 



They have been considered as 

 Xj i secretory organs, answering to 



\ ^^Sg Cy * ne pancreas in vertebrate ani- 



** mals. 



Fig. lO.-Digestive apparatus of Carabu 8 auratus. Fig> ^ which represents fl^ 



digestive apparatus of Carabus auratus, a common beetle, presents to 

 the eyes of the reader the different organs of which we are speaking. 



A is the mouth of the insect, B the resophagus, c the crop, r> the 

 gizzard, E the chylific ventricle, F and G the small and large 

 intestines, and H the anus. 



We will not mention the other parts of the alimentary canal in 



