40 A GUIDE FOR THE STUDY OF ANIMALS 



2. What can be said about the number of species of 

 insects ? 



3. There is said to be great competition among insects. 

 Why ? For what ? 



4. How is the great increase of insects held in check by 

 natural means ? 



5. What are the various habitats of insects ? Give as 

 many as you can with examples of insects that use the 

 habitat. 



6. Give examples to show how greatly the food of 

 insects and the method of obtaining it varies. 



7. Give some illustrations of the great muscular de- 

 velopment of insects. Why is this needed ? 



8. In what various ways are insects protected against 

 their enemies.' Give examples to illustrate your statement. 



9. Show how and why the great numbers of insects have 

 affected the structure and mode of life of the insects. 



Classification 



1. By means of illustrations from your studies of 

 insects show how classification is based upon likeness of 

 structure. 



2. In the same manner show how differences in struc- 

 ture affect classification. 



3. Show how variation in the wings and mouth parts is 

 used to separate insects into orders. 



4. What are the principles of classification .' 



II. REVIEW AND LIBRARY EXERCISE ON INSECTS 

 General Topics 



1. General characteristics of insects. 



2. Principal orders of insects with characteristics and 

 examples of each order. 



