Wing 'venation 



Immediately behind and arising about the junction of the inner 

 with the middle third of this vein is the second longitudinal vein. 

 After completing about half of its course this vein divides into two 

 branches, the anterior and posterior branches of the second longi- 

 tudinal vein. 



Behind the second longitudinal vein and arising about the 

 middle of the wing is the third longitudinal vein. 



The fourth longitudinal vein arises at the base of the wing, 

 and in the last quarter of its course divides into two branches, 

 anterior and posterior. 



The fifth longitudinal vein also arises from the base of the 

 wing ; at about the middle of its course it divides into two branches, 

 anterior and posterior. 



The sixth longitudinal vein is unbranched, arises from the base 

 of the wing, and terminates about the middle of the posterior border 

 of the wing. 



Joining these longitudinal veins with one another are certain 

 transverse veins. 



The most important of these transverse veins is the " the 

 sub-costal " which, arising near the origin of the first longitudinal 

 vein, passes obliquely forwards and outwards to meet the costa about 

 the beginning of the outer third of its course. This is the only 

 transverse vein which is covered with scales. 



Joining the first long vein to the origin of the second long 



vein is a very short transverse vein, " the marginal transverse vein." 



Joining the origin of the third long vein to the second long 



vein is " the super-numerary cross vein." The vein joining the 



third long vein to the fourth long vein is the " mid cross vein." 



The vein joining the fourth long vein to the anterior branch 

 of the fifth long vein is called " the posterior cross vein." 



The first, third, and sixth longitudinal veins are unbranched. 

 The second, fourth, and fifth long veins divide in their course into 

 two branches. The areas enclosed between these branches have 

 received names. The area enclosed between the branches of the 

 second long vein is called "the first submarginal cell"; that between 

 the branches of the fourth long vein, " the second posterior cell," 

 and that between the branches of the fifth long vein, " the anal 

 cell. " Names have been applied to the other areas of the wing 



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