Evolution and Taxonomy 67 



insects. Only by such a system can those comparisons be 

 made which are necessary in any thorough study of the rela- 

 tionship of the orders to each other. Heretofore the students 

 of each order have had their peculiar nomenclature, and in 

 many cases writers treating of a single family have proposed 

 a set of names to be used in that family alone. The matter 

 has been further complicated by the fact that not only have 

 different names been applied to the same vein, but the same 

 name has been applied to different veins. Thus the terms 

 costa and subcosta have been applied by IvCpidopterists to 

 different veins than those that bear these names in other orders. 



There have been .several attempts to establish a uniform 

 nomenclature. Of these that of Redtenbacher is the most im- 

 portant, being based on a much more extended study of the 

 subject than that made by any other author. 



Redtenbacher was the first one to work out a system and 

 apply it to all of the orders of winged insects. And although 

 his system was based on what I believe to be a false theory, 

 and his interpretation of facts in some cases were faulty, I be- 

 lieve that the more essential features of his system can be 

 adopted. 



Although, as I have pointed out above, the fan-type of 

 wing was not the primitive type, it seems desirable to base 

 our nomenclature on this type ; for here we find the maximum 

 number of veins ; and our nomenclature should include the 

 secondarily developed veins of modern insects as well as the 

 primitive veins. 



I have shown that in the preanal portion of the wing of 

 paleozoic insects there were developed five principal veins. 

 These may be designated, beginning with the one on the 

 costal margin of the wings, as costa, snbcosta, radms, media 

 and cubitus. The term media was proposed by Redtenbacher; 

 the others were adopted by him as those sanctioned by the 

 best usage.* I have also shown that in certain insects there 



* Redtenbacher was not the first to recognize media as a principal 

 vein. This was done by Edward Donbleday nearly fifty years ago. See 

 his Remarks on the Genus Argynnis, Trans. Linn. Soc. Vol. XIX, 

 1845. I have adopted the term media in preference to discoidal vein 

 proposed by Doubleday as the latter might be confused with discal vein, 

 the term commonly applied to certain cross veins. 



