196 
THE STUD Y OF INSECTS. 
usually hold the wings erect in a vertical position like 
butterflies; often the fore wings are thus held while the 
hind wings are extended horizontally. The antennae are 
thread-like, and enlarged towards the tip; but in most cases 
the extreme tip is pointed and recurvecl, forming a hook. 
The abdomen is usually stout, resembling that of a moth 
rather than that of a butterfly. This division includes two 
families. 
The Butterflies .—The butterflies fly by day; and when 
at rest they fold the wings together above the back in a 
vertical position. The antennae are thread-like with a club 
at the tip, which is never recurved so as to form a hook. 
The abdomen is slender. This division includes the last 
four families described in this chapter. 
Classification of the Lepidoptera. 
(For Advanced Students.) 
The study of the classification of the Lepidoptera is beset by a 
peculiar difficulty. As these insects are clothed with scales com¬ 
paratively little of their structure can be examined without injury to 
the specimens studied. Fortunately, however, it has been found 
that the various modifications of the framework of the wings afford 
excellent clues to the relationships of the different groups; and these 
modifications can be determined in most cases without serious injury 
to the specimens. The structure of the antennae also can be easily 
studied, and in many cases affords much help in determining the zoo¬ 
logical position of an insect. 
The first step to be taken in the study of the classification of 
these insects is to become thoroughly familiar with the nomenclature 
of the wing veins; this is given on pages 64 to 66. It is a good plan 
to take several of the larger moths and butterflies and make draw¬ 
ings showing the courses of the veins of the wings in each, carefully 
indicating the names or numbers of the veins on the drawings. 
The making of such drawings will be of much use in fixing the ar¬ 
rangement of the veins in the student’s mind. It should be remem¬ 
bered that veins IV and VI are not developed in this order. 
As the scales on the lower surface of the wings are more closely 
applied to the wings than are those on the upper surface, the veins 
can be best seen when the wings are examined from below. The 
