V1. PREFACE, 
been too much neglected by teachers of zoology, while it has 
often been too much insisted upon hy teachers of botany. 
The group of insects has been selected for these exercises 
for obvious reasons. Insects present a great amount of 
variety, and are sufficiently small to require great care in 
their determination ; they can be collected in quantities, and 
can be easily preserved in a fit state for examination, so that 
when other materials fail the teacher can always have recourse 
to them ; and also they are of great importance economically 
to the agriculturist. No doubt the student will not always 
be able to refer an insect correctly to its family by these 
tables; but the failure will do no harm, and the teacher 
should remember that if he wants to give his pupils clear 
ideas, he must not begin by pointing out exceptional cases. 
I have added a short introduction on the principles of 
zoology, in order to give greater completeness to the volume, 
but the whole book is intended to be supplemented by 
lectures, and students who are teaching themselves should 
read Nicholson’s “Manual of Zoology” along with it. At 
the end there is a glossary of the more important terms used 
in describing insects, which the young entomologist will 
find very useful. . 
