OHAPTEE I 



General Characteristics of Insects. 



General Features. The branch of the Animal King- 

 dom called Arthropoda embraces those animals whose 

 bodies are built upon the plan of rings or segments, which 

 fit together by joints made by the folding in and softening 

 of the outer covering, and giving great flexibility to the 

 body. 



Chitine. This outer covering or crust is called chitine, 

 and is the frame -work or skeleton of the insect, answering 

 the same purpose as the bones of the higher animals. 



Divisions of the Body. On examining the body of an 

 ant or a wasp, it is at once noticed that the body is divided 

 by a narrowing in of the outlines into three general divi- 

 sions, — the head, the thorax, and the abdomen. 



The Head. In the head are the eyes, and the mastica- 

 tory organs. It also bears the antennae or 'feelers," — slen- 

 der, hollow and jointed appendages, which are the organs of 

 touch, and, some claim, of hearing also. 



The Thorax. The thorax is the seat of the organs of 

 locomotion. To it are attached the wings and legs. 



The Abdomen. The abdomen contains the digestive 

 and genital organs. As this work is not intended to set forth 

 in detail the physiology of insects, we will only give a brief 

 outline of their internal system. 



The Muscular System. This lies just beneath the 

 chitinous covering or skin of the insect, and according to 

 Newport, it consists of "numerous distinct, isolated, straight 



