354 Annals Entomological Society of America [Vol. XII, 



in the hind wing. The course of these veins is also the same 

 in Cyanauges cyanella, as reference to Figure 4 will show; in 

 this case the separation of Cu and 1st A occurs almost at the 

 base of the wing. 



The obvious conclusion to be drawn from this series of 

 examples is that in the course of evolution, the point of separa- 

 tion of Cu and 1st A moves toward the base of the wing, and 

 concomitant with this change, the oblique basal part of Cu 

 becomes more and more oblique until by the time the point of 

 separation has reached the base of the wing, the formerly 

 oblique free basal part of Cu is in a line with the longitudinal 

 part of Cu. There will thus be no evidence in the venation 

 of this part of the wing in the more specialized Lepidoptera to 

 indicate that it is derived from a venation like that of 

 Mnemonica. What appears to be the posterior arculus is 

 usually obsolescent (as indicated in the Figures by dotted 

 lines), but vestiges of it sometimes traversed by a persistent 

 trachea are present in many Lepidoptera -belonging to widely 

 separated groups, e. g., in Tineidse (e. g., Tineola), Plutellidas 

 (e. g., Pliniaca), Eucleid^ (e. g., Sisyrosea textula), Tortricidae, 

 and possibly in other groups. The question whether this is 

 really the posterior arculus or the base of Mi is not discussed 

 here. In the light of what has been shown to have taken place 

 in more primitive forms, the configuration of veins in the base 

 of the fore wing of the Noctuid, Renia flavipunctalis (Fig. 7), 

 suggests the same course of evolution. The coalescence of 

 the base of the first anal trachea with the cubital trachea, 

 shown in the pupae of some butterflies, and in some of the 

 specialized moths (e. g., Samia cecropia), I am inclined to regard 

 as a secondary connection, following the separation of Cu and 

 1st A at the base. 



The venation of the fore wing of the more generalized 

 members of the NepticulidcC is characterized by the basal 

 coalescence of media and cubitus, a character unique in Lep- 

 idoptera, but whose origin can be explained by assuming 

 that processes similar to what is known to occur in some 

 Trichoptera have taken place. The cubital and medial tracheae 

 lie within the same vein cavity near the base (Fig. 8), the two 

 separating at the point where media bends forward to join 

 radius. This characteristic of the venation of the Nepticulidae 

 can be derived from an ancestral form in which cubitus followed 



