U*V r 'H*K. M*i3F \*n MELBOURliii 
A MANUAL FOR 
THE STUDY OF INSECTS. 
CHAPTER I. 
ZOOLOGICAL CLASSIFICATION AND NOMENCLATURE. 
I. Zoological Classification. 
(For advanced students .) 
In order that the myriad forms of animals may be studied with 
facility some system of classification is necessary. And now that we 
have learned that there exists a blood-relationship between the differ¬ 
ent kinds of animals, that system which most clearly expresses this 
relationship is doubtless the best. This system is termed the Natural 
Classification . 
It is now generally believed that long ago, in early geological 
times, there existed on the earth only very simple animals and plants; 
and that from these simple beginnings more and more complex forms 
have been developed. This growth in complexity has taken place in 
different descendants of these simple primitive beings in very differ¬ 
ent ways. Thus while it is probable that the first animals lived in 
water, and very many still do so, others have become adapted to life 
on the land, and in still others organs have been developed by which 
they can fly through the air. And under each of these conditions we 
find a great diversity of norms, each fitted for some special mode ol 
tife. 
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