G9G THE PANORPOID COMPLEX, iii., 





M, 



R 5 



R 4 



Text-Fig. 106. 

 Forewing of Protohermes davidi Weele, (fam. Corydalidae) , (from 

 van de Weele, but with lettering added, as on p. 535). 



A fair judgment between the two types shown in Archi- 

 chauliodes and Protohermes would, I think, refuse to recognise 

 that one type was at all more predominantly archaic than the 

 other. Both are derivable from a very close common ancestor, 

 in which, on the one hand, no reduction had occurred in the 

 number of branches of M, and, on the other, no additions had 

 been made to the venation from the tips of the veins inwards. 

 Such a type would have to possess the following venation al 

 characters : — At least six branches of Rs, viz. a dichotomic fork 

 of R 2 , a similar one belonging to R 3) and the original fork of 



R4+5 still preserved; four branches of jVJ 2 4) arranged in the 



original dichotomic manner; and a normal, archaic, three- 

 branched Cu. 



This common type will be seen at once to be the Archetype, 

 not only of the family Corydalidae, but also of the -family 

 Sialidae, and hence of the whole Suborder Sialoidea. We have 

 now to consider what modifications are required in it, in order 

 that it may also be the Archetype of the Raphidioidea, and 

 therefore of the Avhole Order. 



Text-fig. 107 shows the venation of Raphidda maculicollis 

 Steph. The specialisations to be seen in this type are chiefly 

 those by which the original courses of the main veins and their 

 branches have been greatly altered from the normal condition. 

 M has become strongly fused basally with R ; and, in the fore- 

 wing, C\\ has become very strongly fused with M. The ter- 

 minal twigging of R lb and the upper branch of R 2 are clearly 



