WING VENATION 



19 



cubital stem, Tillyard maintains is the branch Cug. In other 

 words, the primary bifurcation of the cubital vein takes place 

 much nearer the base, and the forked cubital vein of Comstock 

 and Needham represents its anterior branch only. The primi- 

 tively three-branched cubital vein is present in the lower orders, 

 as well as among Holometabola, and it is evident that it is to be 

 regarded as a fundamental character in any hypothetical venation 

 scheme for insects. 



The views of Redtenbacher regarding the significance of the 

 alternation of convex and concave veins are supported in general 

 by modern researches. If, for example, two convex veins occur 



Fig. 9. Hypothetical scheme of wing venation according to Lameere. 



in proximity to each other on an insect wing, a strong presumption 

 arises that an intervening concave vein has either been merged 

 with one or other of the convex veins, or has been suppressed. 

 Reasoning along these lines has helped to establish the identity 

 of veins in both fossil and recent insects. The important 

 researches of Lameere (1922) are largely based upon deductions 

 of this kind, drawn from a study of both recent and fossil insects. 

 He concludes that no living insect possesses as complete a venation 

 as that found in the early fossils of the coal measures. In this 

 contention he affords strong support to the views of Redtenbacher, 

 which were not accepted by Comstock (1918). Lameere's study 

 of the Palaeodictyoptera led him to stress the importance of 

 following the alternation of convex and concave veins, and, 

 according to him, there are six principal veins on the primordial 



