THE PARTS OF A LOCUST. 15 



two pairs of jaws, the mandibles and the maxillcB ; and 

 a tonguelike organ, the hypopharynx. The jaws open 

 sidewise instead of up and down, as do the jaws of 

 the higher animals. The upper pair of jaws are called 

 the mandibles ; the lower pair of jaws the maxillce. 

 Each maxilla bears a palpus ; these are the maxillary 

 palpi. The labium bears a pair of palpi ; these are 

 the labial palpi. 



LESSON IV. 



THE PARTS OF A LOCUST (CONTINUED). 



The Appendages of the Thorax, the Legs. 



The thorax is the middle one of the three regions 

 of the body (see Lesson I and Fig. 3). The append- 

 ages of the thorax are three pairs of legs and two 

 pairs of wings. In this lesson we will study the 

 legs. 



1. Study carefully one of the fore legs of the 

 locust and observe that it is composed of several 

 parts or segments. Each of these segments of the 

 leg has a distinct name. As these names are often 

 used in descriptions of insects, it is necessary to learn 

 them. 



2. The first segment of the legs, the one that is 

 joined to the body, is nearly globular in outline ; this 

 is the coxa (cox' a). 



3. The second segment of the leg is much smaller 

 than the coxa ; this is the trochanter (tro-chan'ter^. 



4. The third segment of the leg is the principal 

 one ; this is the. femur {fe'mur). Its name is the same 

 as that of the principal bone in the human leg. 



5. The fourth segment of the leg is nearly as long 



