4 INVERTEBRATE ZOOLOGY 
Bxercise 3. Remove a metathoracic leg and draw an outline 
of it on a scale of 5. Its different segments, beginning 
with the proximal one, i.e., the one nearest the body, are 
the following: the coxa, by which the leg articulates with 
the body ; the trochanter, a very small segment ; the femur 
or thigh, a long segment ; the tibia or shank, also long ; the 
tarsus or foot, which is composed of five small segments, 
the last one of which bears the two claws. Label all of 
these. 
Exercise 4. Remove a mesothoracic wing, extend it, and draw a 
picture of it on a scale of 5, indicating its venation. 
Save your specimen in a dish of formalin or alcohol for future 
use. We shall reserve the detailed study of the mouth-parts 
until the grasshopper is taken up, when the mouth-parts of the 
various orders of insects will be studied together. The internal 
anatomy of all insects is exceedingly similar, and it will not be 
necessary to study it in more than one animal; we select the 
grasshopper as being the one best suited. 
