HOW TO KNOW THE BUTTERFLIES 



two extend to the margin of the wing as a single 

 vein, which for this reason is marked Sc-f-R,. It 

 will also be seen that the radial sector extends to 

 the margin of the wing as an unbranched vein, 



marked R s . 



In some butter- 

 flies a short spur 

 extends from the 

 subcosta near the 

 humeral angle of 

 the wing ; such a 

 spur is termed the 

 humeral vein 

 (Fig. 7, H). 



The thin spaces 

 of thewings which 

 are bounded by 

 the veins are called 

 cells. In descrip- 

 tions of wings, es- 

 pecially in indicat- 

 ing the location 

 of markings, it is 

 often desirable to 

 refer to one or more cells. It is necessary, there- 

 fore, to have a nomenclature of the cells of the 

 wing, as well as of the wing-veins. 



14 



Fig. 8. 



-Venation of the wings of 

 swallow-tail. 



