10 INVERTEBRATE ZOOLOGY 



margin of the mesosternum and of. that of the first 

 sternite with the metasternum, also the attachment of 

 the legs. 



Exercise 5. Remove a metathoracic leg and draw an outline of it 

 on a scale of 3. The segment by which it articulates with 

 the body is the coxa; the next segment is the trochanter, 

 which in the grasshopper, however, is not a free segment, 

 but is fused with the following one, the femur ; the latter 

 is the largest segment of the leg and has V-shaped muscle 

 impressions on its surface; the next segment is the tibia 

 or shank ; the end segment is the tarsus or foot, which is 

 made up of five smaller segments ; the terminal one of 

 these bears two claws between which is a structure called 

 the pulvillus. This organ is an adhesive pad which enables 

 the animal to walk and spring on smooth surfaces. Label 

 all of these parts. 



Exercise 6. Draw an outline of the face on a scale of 5 or 6. 

 The large plate which forms the top, front, and sides of 

 the head, in which the eyes, ocelli, and antennae are situ- 

 ated, is called the epicranium. The sides of the epicranium, 

 back of the eyes, are the genae, the top is the vertex, and 

 that part which forms the anterior surface is the front. 

 Ventral to the epicranium is a broad, short, median plate 

 called the clypeus, beneath which is the upper lip. The 

 antennae are the first pair of appendages. Label all of 

 these parts. 



The mouth-parts. These consist of the median upper lip or 

 labrum, the paired mandibles, the paired maxillae, the median hypo- 

 pharynx, and the paired under lip or labium. The paired mouth- 

 parts are the second, third, and fourth pairs of appendages. 



Exercise 7. Remove the labrum with scissors and draw it on a 

 scale of 5. 



