XV111 INTRODUCTION. 



tions. They possess the five senses, and are en- 

 dowed with wonderful instincts. The organs of 

 nutrition and generation are as perfect as those of 

 more elevated orders. 



Insects have been called hexapodes, from their 

 having six feet. Their body is for the most part 

 composed of various joinings or articulations. 

 These joinings are comprehended in the head, tho- 

 rax or chest, abdomen or belly. 



The head has a moveable junction or articula- 

 tion with the second division or thorax, in the 

 greater number of insects. The mouth, antennae, 

 and eyes are parts of the head. 



Mouth. All insects either divide their food or 

 suck it. In all, therefore, the mouth is modelled 

 to answer one or other of these purposes. 



In those which divide their food, the parts of 

 the mouth are, an upper lip, and an under lip fixed 

 to a piece called the chin ; between these two there 

 are four lateral pieces, two on each side ; the two 

 upper are called mandibles, the two lower maxillae 

 or jaws. To the two lower are attached one or more 

 moveable adjuncts called palpi. The under lip 

 has also two appendices, called labial palpi. 



With the palpi the insect seems to judge of the 

 quality of its food ; which it touches and examines 

 with these organs. The mandibles or upper jaws 

 cut the food. The lower jaws or maxillae divide 

 and masticate it. The motion of these parts is 

 horizontal and not vertical, as with us : the upper 

 and under lips move forwards, backwards, and verti- 



