106 LABORATORY EXERCISES 



a. Read 339 of the text. Answer the following questions 

 for each insect you can study : 



1. How many regions has the body? Are they equally 

 distinct in all the insects examined? 



2. How many pairs of legs has the insect? To which region 

 of the body are they attached? What ones are put forward 

 at the same time? 



3. How many pairs of wings has the insect? Are all of them 

 used for flying? To what body region are they attached? 

 What are the markings of the wings? 



4. How many segments are there in the abdomen? Are all 

 the segments of the same shape and size? Are any structures 

 attached to these segments? 



5. What is the shape of the head? What parts of the head 

 can you distinguish? What is the shape and size of the parts 

 of the mouth? How are they used? What does the insect eat? 



6. Can you find the eyes of the insect? How many are there? 

 What is there remarkable about the eyes of insects such as the fly? 



b. By digging in a barnyard or in a strawberry patch, or 

 even in the open field, you can usually find " white grubs," the 

 larvae of the May beetle. Examine one carefully, and describe 

 it. What is its color? Can you count its body segments? 

 Has it "feet?" To what parts are they attached? Describe 

 the parts of its mouth. What does the grub feed upon? 



c. If possible, find a spider's web; study its construction, 

 and draw it. Are the webs of all spiders alike? Out of what 

 do spiders spin webs? Why do they spin webs? 



d. Between late fall and early spring you will usually be 

 able to find the large, dense cocoons of the cecropia moth. 

 They are brown, and attached to the branches of such trees 

 and shrubs as the apple, cherry, willow, lilac, maple, and 

 elder. Get several, if possible, and put them into a box with a 

 cover of wire netting. 



