064 THE PANORPOID COMPLEX, iii.. 



Superfamily TORTRICTNA. 



The Codlin-inoth, Carpocapsa pomonella (Linn.) afforded ine 

 a plentiful supply of pupae for this group. The pupa being- 

 small, and the wings delicate, the dissections were not at all 

 easy. 



The basal tracheation of the pupal forewing is shown in Plate 

 xxxiv., fig. 22. It differs very little from that of Wingia 

 (Text-fig. 90), so that there is no need to figure the whole wing 

 separately. The principal differences are that, in the forewing 

 of Carpocapsa, the stem of R 4+5 persists at metamorphosis, so 

 that the basal cell and radial cell or areole remain separate (a 

 more archaic condition than that seen in Wingia) ; that Cu ap- 

 proaches basally so close to M that the formation of the separate 

 vein M 5 is prevented (in Wingia, the formation of this vein 

 can just be made out in the early pupa) ; and that there is no 

 kink in 1A at the point where 2A fuses with it. 



In discussing the evolution of the cubito-median Y-vein (Sec- 

 tion iii.), it was pointed out how all the successive stages of 

 specialisation, leading to the obliteration of M 5 , and finally to a 

 definite fusion between Cu x and M 1 _ 4> could be seen in a single 

 Order, or even in a single family, such as the Bhyacophilidae. 

 The same line of advance is here made evident within the Hetero- 

 neura, the stage shown in Carpocapsa being closely equivalent to 

 that indicated as the last stage (Text-fig. 42 d) in the Order 

 Trichoptera. But there is one important difference, viz. that 

 the fusion in Carpocapsa takes place, not between M' 1 _ 4 and 

 Cui, but between M 1 _ 4 and the main stem of Cu. This is 

 not due to any movement of the cubital fork distad, for it is 

 quite evident that this fork itself is migrating basad (and, 

 indeed, in many advanced Heteroneura, trachea Cu 2 may be so 

 far split back from Cuj as to originate separately from it on 

 the alar trunk) ; but it is due to the general tendency for the 

 basal formations as a whole to move closer to the base of the 

 wing in this Suborder, and is part of the whole line of evolution 

 by which, in the end, all those basal specialisations which no 

 longer serve any useful purpose become obliterated. 



The tracheation of the pupal hindwing of Carpocapsa is 

 shown in Text-fig. 89, for the special purpose of illustrating 

 (a) the dominance of R x over Sc, as in the Tineina, and (b) 

 the further weakening of 1A, and the dominance of 2A in the 

 formation of the anal Y-vein. We may note also the close 



