IV 
PREFACE . 
the present work even if it were possible to describe all of 
our species. 
Although much pains has been taken to render easy the 
classification of specimens, an effort has been made to give 
the mere determination of the names of insects a very sub¬ 
ordinate place. The groups of insects have been fully char¬ 
acterized, so that their relative affinities may be learned; 
and much space has been given to accounts of the habits 
and transformations of the forms described. As the needs 
of agricultural students have been kept constantly in view, 
those species that are of economic importance have been 
described as fully as practicable, and particular attention has 
been given to descriptions of the methods of destroying 
those that are noxious, or of preventing their ravages. 
An effort has been made to simplify the study of in¬ 
sects as much as possible without sacrificing accuracy in the 
descriptions. Only such morphological terms have been 
used as were necessary to accomplish the object of the book 
in a satisfactory manner. And so far as possible a uniform 
nomenclature has been used for all orders of insects. The 
fact that writers on each order of insects have a peculiar 
nomenclature has been a serious obstacle to the progress of 
entomology; this is especially true as regards the nomen¬ 
clature of the wing-veins. It has been necessary for the 
student in passing from the study of one order of insects to 
that of another to learn a new set of terms; and in many 
cases writers on a single family have a peculiar nomenclature. 
The present writer has endeavored to remove this 
obstacle by making a serious study of the homologies of the 
wing-veins, and by applying the same term throughout the 
work to homologous veins. The result is that the student 
is required to learn only one set of terms ; and in applying 
these terms there will be brought to his attention in a forci¬ 
ble manner the peculiar modifications of structure charac¬ 
teristic of each order of insects. Heretofore, with a differ¬ 
ent nomenclature for the wing-veins of each order such a 
