688 THE PANORPOID COMPLEX, in.. 



order, because they have been studied in this Section, and a 

 tabulation of their characters for comparison with the older 

 groups may prove of great value later on in helping to solve the 

 problem of their origin. On the other hand, the fossil Palaeon- 

 tinidae have been omitted; for, as already indicated, there is no 

 proof that they have been derived from the old Homoneurous 

 stem of the Order along the same line of descent as our present- 

 day Heteroneura. They are best treated as an entirely separate 

 group, until, perhaps, further discoveries, or more detailed study 

 of the existing fossil types, may have demonstrated conclusively 

 where they properly belong. 



Text-fig. 103 gives a diagrammatic representation of the wing- 

 venation of the Archetype of the Heteroneura. The Table shows 

 conclusively that, of all existing Heteroneura, the Cossidae stand 

 far nearer to this Archetype than do any other group . Thus 

 Dr. Turner's name of Protocossidae for the archetypic family of 

 the Suborder is fully justified. Next to the Cossidae would 

 come the most archaic Tineina, such as Titanomis, and then the 

 Castniidae and the bulk of the Tortricina and Tineina. The 

 groups above these are more highhy specialised. 



It is interesting to compare the Archetype of the Heteroneura 

 with that of the Homoneura, i.e. of the whole Order Lepidoptera. 

 The characters in which it is specialised may be briefly stated 

 as follows : — ■ 



(1) Absence of the distal forking of Sc. 



(2) Absence of the distal forking of R 1# 



(3) In forewing, R2+3 forks nearer to base than does R^+s. 



(4) In hindwing, Sc and li 1 are fused distally. 



(5) In hindwing, Rs is a simple, unbranched vein. 



(6) M 4 is already placed in a transverse position, resembling 

 a cross-vein, and its trachea is, at the most, only feebly de- 

 veloped . 



(7) The cubito-median Y-vein, though present, is never so 

 typically developed as in the Jugo-frenata . 



(8) 3A is absent from the forewing. though present in the hind. 



(9) Only a single Y-vein is present in the anal area of the 

 forewing . 



(10) 1A and 2A are fused near the base in the hindwing, to 

 form an anal Y-vein. 



(11) The following cross-veins are absent: — sc-r, cu-a, ia lf 

 ?'« 2 , and sa. 



(12) The shape of the wings is much altered from the ori- 



