AN 
INTRODUCTION 
TO 
ENTOMOLOGY. 
LETTER XXVIII. 
DEFINITION OF THE TERM INSECT. 
Waar is an insect? This may seem a strange ques- 
tion after such copious details as have been given in my 
former Letters of their history and economy, in which it 
appears to have been taken for granted that you can an- 
swer this question. Yet in the scientific road which you 
are now about to enter, to be able to define these crea- 
tures technically is an important first step which calls for 
attention. You know already that a butterfly is an insect 
—that a fly, a beetle, a grasshopper, a bug, a bee, a 
louse, and flea, are insects—that a spider also and centi- 
pede go under that name; and this knowledge, which 
every child likewise possesses, was sufficient for compre- 
hending the subjects upon which I have hitherto written. 
_ But now that we are about to take a nearer view of them 
—to investigate their anatomical and physiological cha- 
racters more closely—these vague and popular ideas are 
VOL. II, B 
JAN 1 7 1957 
