24 
THE GRASSHOPPER 
tains the two auditory sacs, and two abdominal spiracles, 
one on each side. Fourteen other spiracles are found on the 
next seven segments, seven spiracles on each side. The last 
two segments have no spiracles. Instead they are modified 
for reproduction. The spiracles are used for breathing and 
the auditory sac, possibly, for hearing. In the female the last 
segment of the abdomen is provided with two pairs of blunt 
spines that serve as an egg-laying device called ovipositor. 
LABORATORY STUDY 
Work out the divisions of the body of the grasshopper: head, thorax, 
and abdomen; the position of eyes. How are the antennae related to 
the eyes? How many distinct mouth parts are there? The teeth or 
jaws are the most useful in getting food. How do the jaws work? 
Sketch the head to show these parts with the mouth open. 
Notice the attachment of the head to the thorax. The head fits into 
the thorax. The loose anterior (front) portion of the thorax is the pro¬ 
thorax (forward thorax). The first pair of legs is attached to it. Sketch 
the prothorax to show it and its legs. The portion of the thorax back of 
the prothorax is divided into two regions: the mesothorax (middle 
thorax) and the metathorax (back thorax). The line between them is 
not clear. Sketch these parts together with the legs and the wings. 
The jumping legs are attached to the metathorax; the outer wings to 
the mesothorax; the inner wings to the metathorax. The inner wings 
are used in flying. The leg of the grasshopper consists of : (1) a small 
section close to the body (the trochanter); a long muscular part free 
from spines (femur); a slender spiny part (tibia); and three segments of 
the foot (tarsus). The last segment of the foot is furnished with hooks 
which help the grasshopper in climbing, while the spines on the tibia pre¬ 
vent slipping as the grasshopper jumps. The large muscles in the femur 
of the last pair of legs, the spines on the tibia, and the hooks on the tar 
sus, are special adaptations which help the grasshopper in various ways. 
Notice the tapering abdomen, composed of ten segments (rings), or 
parts of segments. Notice the depression and membrane in the first 
segment. This is the auditory organ, but it is not a true ear. Sketch 
the abdomen to show its features. The spiracles are located on the sides 
of the abdomen and thorax. 
8. Excretion.- —The gaseous waste', carbon dioxide, passes 
from the body into the spiracles and escapes into the air. 
