THE CABBAGE BUTTERFLY. 87 



margin, or more commonly the costa; the margin farthest 

 from the body is called the outer margin; the other mar- 

 gin is called, on the fore wings the hind margin, on the 

 hind wings the internal margin. The angle by which the 

 wing joins the body is called the base; the angle between 

 the costal and outer margins is called the apex; the 

 other angle is called the posterior angle on the fore wings, 

 the anal angle on the hind wings. The branches of the 

 subcostal vein are called the subcostal veinules, and like- 

 wise those of the median vein are called median veinules; 

 and both are numbered first, second, third, etc., from the 

 front. On the basal half of each wing, between the sub- 

 costal and median veins, is an obovate inclosure, called 

 the discal cell, or more often simply the cell. The space 

 outside this, occupied by the terminal veinules, is called 

 the discal space, or often simply the disk. Extending 

 across the ftisk from the cell to the outer margin of the 

 wing is a short, straight vein situated about halfway be- 

 tween the subcostal and median veins, but appearing not to 

 be a branch of either, and hence called the independent vein. 1 



1 The names of veins here given are those found in nearly all our 

 descriptive works on butterflies and moths. There has been little uni- 

 formity hitherto in the names used by writers in the different groups, 

 each of the principal groups having developed a nomenclature of its own. 

 Professor Comstock has proposed for the veins of the wings of all insects 

 a uniform nomenclature which seems likely to be adopted. Applying 

 this system to butterflies and moths (Lepidoptera) , the principal veins are 

 as follows : 



Costa. On the costal edge of the wing. 



Subcosta. Improperly called the costa by writers on the Lepidoptera. 



Radius.' Improperly called the subcosta by writers on the Lepidoptera. 



Media. The base of this vein is wanting, and its branches are joined 

 to adjacent veins. It is three-branched. Its middle branch is the so-called 

 independent vein. 



Citbitus. This vein is two-branched, but appears to be three-branched 

 in most butterflies, as the third branch of media is joined to it. 



Anal Veins. There may be one, two, or three of these. In most 

 butterflies there is one anal vein in the fore wing, and there are two in 

 the hind wings. 



Costa, subcosta, and the anal veins are simple in all Lepidoptera. 



