HEXAPODA . 
65 
The principal veins may be designated by numbers as well 
as by names ; the following table indicates the correspondence 
of the names and numbers : 
Cubitus = vein VII. 
1st anal vein = vein VIII. 
2d anal vein = vein IX. 
3d anal vein = vein XI. 
Costa = vein I. 
Subcosta = vein II. 
Radius = vein III. 
Media = vein V. 
It was formerly believed that in certain insects three other 
longitudinal veins were present ; these were numbered IV, VI, 
and X respectively ; hence these numbers are omitted in the 
above table. 
At the time the first edition of this book was written, it was 
thought best to designate the veins by numbers; and conse¬ 
quently numbers are used in the following pages much more 
generally than are the names of the veins. But owing to a 
lack of uniformity in the numbering of the veins by different 
writers, it is now clear that the names are to be preferred. In 
Fig. 79.—Diagram representing the typical arrangement of the wing-veins, includ¬ 
ing the four more important cross-veins: /6, numeral cross-vein; r-m , radio- 
medial cross-vein ; m, medial cross-vein ; m-cu, medio-cubital cross-vein. 
the lettering of figures abbreviations of the names can be used 
as is done in Figure 79. 
The divisions of a branched vein are numbered, beginning 
with the one nearest the costal margin of the wing ; and 
these numbers are indicated by sub-figures. For example, 
6 
