FOR THE USE OF TEACHERS. 



No. ll. 



Leaflet 



On Nature Study. 



Especially Adapted to the Use of Children in Schools 

 IN Rural Districts. 



PREPARED BY THE 



FACULTY OF PURDUE UNIVERSITY. 



A STUDY OF OUR INSECT ENEMIES. 

 In Three Fifteen-Minute Lessons. 



By Prof. James Troop. 

 I. 



ISo children have a better opportunity for studying the habits of 

 insects than those of you who live in the country; and I suppose it is 

 true that the most of you do know a great deal more about the ways of 

 insects in general than your city cousins; but I wonder how many of 

 you have any idea how many kinds of insects there are in the world? I 

 do not suppose that any one knows exactly, but I think wc would be 

 safe in saying that fully four-fifths of all the animals in the world 

 lielong to this class. This is a good many, you say. Yes, indeed, it 

 is a good many, but you will see when you get a little older that I have 

 not stated it any too high. 



In studying insects it has been found necessary to divide them into 

 classes as a botanist classifies his flowers. The classification that has 

 been adopted is based largely upon the wings of insects. Those having 

 thin, membranous wings are put in one class; those having scale wings 

 in another; and those having sheath wings in still another, and so on. 



NOTE TO TEACHER.— The time at which tliese varioHs lessons should 

 be given will depend somewhat upon the latitude and advancement of the 

 season; but since it is desirable to {five the lessons about the time the obser- 

 vations can be made it will be necessary to place them about three weeks 

 apart. 



