68 Joh7i Henry Coinstock 



is developed, secondarily, a longitudinal vein between radius 

 and media, for this I propose the Xoxra. premedia ; and also in 

 the same insects there is developed a longitudinal vein be- 

 tween media and cubitus, this I designate as postinedia. 



Following the system of Redtenbacher these veins may also 

 be designated by Roman numerals. The equivalence of the 

 numbers and names of the veins of the wing is indicated bj- 

 the following table ; also the nature of the veins. 



I. — Costa convex. 



II. — Subcosta, usually concave, secondarily. 



III. — Radius convex. 



IV. — Premedia .... concave. 



V. — Media convex. 



VI. — Postmedia .... concave. 



VII. — Cubitus convex. 



VIII. — First anal .... concave. 

 IX. — Second anal . . . convex. 

 X. — Third anal .... concave, 

 et al. 



It will be seen irom this table that if we consider subcosta 

 a concave vein, which it has come to be in the larger num- 

 ber of the orders of insects, there is a regular alternation of 

 convex and concave veins, when the maximum number of 

 veins is present. And hence the convex veins are desig- 

 nated by odd numerals and the concave veins by even numer- 

 als ; this is one of the chief features of Redtenbacher's system, 

 and an exceedingly useful one. 



If this system be applied to the anal area, and I believe it 

 is best that it should be, all convex anal veins must be desig- 

 nated by odd numerals. In those orders where the anal area 

 has been greatly specialized by addition, {e. g., Orthoptera), 

 this would naturally follow ; for there we find a regular alter- 

 nation of concave and convex veins. But in certain other 

 cases it is not so obvious. In those Lepidoptera in which 

 three anal veins are pre.served, the first (vein VIII) is con- 

 cave, and doubtless represents the primitive anal furrow ; the 

 second is convex and is obviously vein IX ; but the third is 

 also convex ! Shall this be designated as vein X, or as vein 

 XI ? It seems to me better that we consider vein X absent. 



