344 



THE WINGS OF LEPIDOPTERA 



wings be examined. But it is clearly indicated by the tracheation of the 

 wings of pupas ; and after one has learned what has taken place by a study 

 of pupal wings, it is easy to find vestiges of the lost part of vein R4+0 in the 

 wings of adults. 



The wings of Anosia plexippus illustrate well these facts. Figure 354 

 is a reproduction of a photograph of a wing of a pupa of this species, and 



Fig. 354.— Fore \vu 



j[ .III Odd plexippus. 



Figure 355 illustrates the tracheation of this wing. In this wing, trachea 

 R4+5 separates from the radial trachea near the base of the wing. Figure 

 346 represents the adult wing of the same species. In this wing a vestige 

 of vein R4+5 is to be seen near the end of the discal cell. 



Ri R 



2d A 



Fig- 355- — Tracheation of the wing represented in Figure 354. 



An extended examination of the wings of Lepidoptera made by Headlee 

 led to the conclusion that this splitting back of vein R4+5 has taken place 

 throughout the Rhopalocera, and has not occurred in the Heterocera. 



