22 
THE GRASSHOPPER 
of the abdomen are eight regularly arranged, small openings, 
spiracles (spir'a-k’ls), which lead into branching tubes, tracheae 
(tra'ke-e). There are also two spiracles on the mesothorax. 
The branching tracheae are kept open by means of skeleton¬ 
like rings so that the pressure of the muscles and other organs 
cannot flatten or close them. The tracheae continue to 
branch until the subdivisions are so small that they can be 
seen only by aid of the microscope. These fine branches 
extend to the minute cells of which the body of the grass¬ 
hopper is composed. Here the oxygen passes to the living 
protoplasm of the cells 
and carbon dioxide is 
given off to the air 
which is in these breath¬ 
ing tubes. This use of 
the oxygen by the proto¬ 
plasm and the giving off 
of the carbon dioxide is 
respiration. (See Res¬ 
piration, page 5.) 
7. Body Regions. — 
The grasshopper has 
three body regions : the 
head, the thorax, and the abdomen. Each of these regions 
is adapted to particular kinds of work. The head struc¬ 
tures are adapted to food-getting, seeing, and feeling. The 
thorax has appendages for locomotion: walking, jumping, 
and flying. The abdomen is adapted to breathing, hearing, 
and reproduction. 
The Head. — On the front of the head are three simple 
eyes and on the sides of the head two compound eyes. Near 
the simple eyes are two antennae for feeling. The mouth 
has several special parts for food getting. (See Figure 8, 
page 21.) These parts are an upper lip (labrum), and a lower 
lip (labium) for moving the food into the mouth. Inside 
Figure 9. — The Jumping Leg of the 
Grasshopper. 
Why is the femur so much larger in this leg 
than in the one just in front of it ? 
