FOR WAGGONER’S BIOLOGY 
69 
upper side of the esophagus. Locate the ventral nerve cord. This 
is ventral to the digestive system. Do you find ganglia along the 
course of this cord? Where? 
IV. Name the structures present in a locust which adapt it to 
its habitat. 
V. Examine as many different stages of development in young 
locusts as possible. Note especially the changes in wings and in 
size. The type of development found in the locust is known as 
‘‘ incomplete metamorphosis.” 
EXERCISE 68 
THE MAY BEETLE 
If desired, some other beetle may be substituted for the May 
beetle (the so-called June bug ”). 
I. The External Structure. Examine the specimen which is 
provided. Note its shape and color. 
1. The Head. What is the nature of the eyes? Note the 
character of the antennae. Compare with the locust. Compare 
the mouth parts with those of the locust. 
2. The Thorax. Are the legs all alike? Explain. What is the 
use of the barb and the claws? How many wings has the beetle? 
Compare them in regard to structure, size, shape, and function. 
Note and explain how the posterior wings are folded. 
3. The Abdomen. What is its structure? Its shape and size? 
Compare with the remainder of the body. Find the spiracles. 
II. The Stages of Development. Note the shape, the color, and 
the size of the larva (the grub). Compare the.head, thorax, and 
abdomen with those of the adult. Describe the covering of the 
larva. When does the beetle damage plants — in the adult or 
in the larval stage? What kind of a poison should be used to de¬ 
stroy this insect? Why? Examine the pupa of the same beetle. 
Compare with the larva. The type of development found in the 
