70 INSECTA 



sonous character when exposed to the air. For this reason care 

 should be taken to get it fresh or it will have no effect. 



Spraying Exercise. — Compute the proportions required for 

 one gallon of an arsenic spray and of one contact insecticide. 

 Carefully prepare each. Spray any plants you find infested 

 by insects with the kind which the condition of the plants leads 

 you to think is required. Examine these plants in a day or two 

 and record results. Also place a sprig of the plant sprayed with 

 each insecticide in separate breeding jars. Label each and com- 

 pare results. 



Insect Studies 



Note. — For a first morphologic study, use large grasshoppers 

 and take all of the External and Internal Morphology. Then 

 follow this with the Systematic Study for Arthropod Branch 

 Characteristics; follow this with the Class and the Ordinal 

 Study. The grasshopper belongs to Branch, Arthropoda; 

 Class, Insecta; Order, Orthoptera. 



For other insects, follow the same plan as for the grasshopper, 

 omitting any questions which do not apply to the insect in 

 hand. The Internal Morphology may also be omitted. This 

 plan will give a comparative study of insects, showing their 

 morphology, and bringing out the principles of classification for 

 the branch, class, and orders to which the insects belong. 



The student will notice that all insects belong to the same 

 branch and class, but to different orders. Notice carefully the 

 branch characteristics and then the class characteristics. 

 Upon what is the classification based? Is it structure? Is 

 it plan of structure? Is it development? 



THE GRASSHOPPER 



Morphophysiologic Study 



A. External Morphology 

 I. The Skeleton. 



1. Is the skeleton external or internal? 



2. Character or composition? 



3. Uses? 



