634 THE PANORPOID COMPLEX, hi., 



The Archetype of the Lepidoptera, as here defined, includes, of 

 course, characters taken from the three archaic Jugo-frenate 

 families of the Homoneura, viz. the Micropterygidae, Eriocrani- 

 idae and Mnesarchaeidae. It was realised from the first that 

 the question of the correct ordinal position of these families was 

 of the greatest importance; and this was one of the reasons 

 that prompted me to devote special attention to them, giving a 

 series of papers on them, to be read concurrently with those of 

 which this paper forms a part. As soon as the study of these 

 three families had progressed sufficiently, I became convinced 

 that they were indeed archaic Lepidoptera, and nothing else; 

 and hence I do not now hesitate to use them in constructing the 

 Archetype of that Order. But, in order that those who may 

 still hold an opposite view may be convinced that it makes no 

 essential difference whether they be included or not, from the 

 point of view of the archetypic wing-venation, the alterations 

 which would be caused in the definition of the Archetype are 

 here set down, as follows : — 



(A) If the family Micropterygidae (s.str.) be excluded, then 

 there will be no difference at all in the Archetypic wing-venation. 

 For Sc is distally forked in Prototheora and in Mnemonica, Hi 

 is distally forked in both Mnemonica and Eriocrania, sc-r is 

 present in Mnesarchaea, the other cross-veins in numerous genera, 

 and likewise the fusion of 1A with Cu 2 in the hindwing. 



(B) If all the three families of the Jugo-frenata be removed 

 from the Lepidoptera, then the Archetype must be modified, in 

 so far that R : will be no longer forked, and the cross-veins 

 sc-r, ia 2 , sa, will be absent; since, as far as I know, these charac- 

 ters do not occur outside the Jugo-frenata. All the other charac- 

 ters are to be found in one or more of the remaining families of 

 the Order. As the differences mentioned are not of very great 

 importance, it will readily be seen that no essential alteration 

 will be needed in the venation of the Archetype, even if the 

 whole of the Jugo-frenata were to be removed from the Order. 



The relationship) between the two Orders Trichoptera and Lepi- 

 doptera is a close one, comparable with that between the Mega- 

 loptei'a and Planipennia, but not so close as this latter. In 

 each case, it is the aquatic side-branch (Trichoptera or Megalop- 

 tera) which has remained, on the whole, in the more archaic 

 condition, while the main terrestrial stem (Planipennia or Lepi- 

 doptera) has advanced, and branched out in many new direc- 



