LESSON 10 
NOTES 
The lessons upon the shade tree insects, like the lessons upon 
the tree diseases, must necessarily be more technical, and conse- 
quently more difficult, than the other lessons of the course. 
In the preparation of these lessons, it has been our aim to 
make them simple and brief yet contain as much practical informa- 
tion as possible that will help you in your work and in studying the 
references given in the bibliography. 
The lessons are not intended simply for study while you are 
taking the course and answering the examination questions, but 
they are intended also for future reference while working as a Tree 
Surgeon. 
Entomology was first studied as a past time or as a pure 
science. It had to do largely with the study of the dead insects, 
classifying and naming them or arranging them into collections 
for exhibition purposes. This is now generally spoken of as sys- 
tematic entomology. 
