CHAPTER VIII. 



A REPRESENTATIVE ANIMAL: THE LOCUST OR 

 THE CRAYFISH. 



72. Most pupils in the country schools or in the small towns will 

 know in a general way where to find either of these animals. Either 

 will serve very well as an introductory type; but the writer prefers 

 the locust for field work and the crayfish for the laboratory study. 

 // there is not time to study both animals, one portion of the class might 

 well study one and the rest the other. This would make it possible 

 to compare the two, point by point, in a manner that will be highly 

 valuable. 



In city schools particularly some means for giving the animals a 

 reasonably natural home in the laboratory should be devised. 

 Crayfish can be kept indefinitely in aquaria; and the grasshoppers 

 will thrive for sufficient time in large boxes in which are kept some 

 of the plants necessary for their food. Wire screening over two 

 sides of the box will make it possible to watch them continuously. 



The Locust (''Grasshopper"; any large species'). 



73. The Field Exercises. This should be done early 

 in the fall, if possible, and the studies should actually 

 be made in the field by the individual pupil. The follow- 

 ing outline will indicate to the student some of the more 

 interesting topics for study. 



A. Habitat and Habits of Life. Where do you find the 

 locusts most abundant? Is their number or activity 

 affected by temperature? By moisture or drouth? 

 Evidences. Examine on different kinds of days, and 

 compare. When, during the day, are they most active? 

 What about them at night? 



Do they show any preference for any particular type 



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