BY R. J. TILLYARD. 



63^ 



Sci Sc - ^ ia R 



* R, 



I A 



Lu, 



CU 2 CU;_ 



Text-Fig.76. 

 Wings of the Archetype of the Division Jugo-frenata. Lettering as on 

 p. 535. 



(2) The loss of the original obliquity of M 4 after fusion with 

 Cu la . This, again, is due to reduction in size. In the larger 

 Hepialidae, the obliquity is retained ; while, in the Prototheoridae, 

 the reduction of M 4 to the appearance of a cross-vein has not 

 proceeded so far as in the Jugo-f renata . (Reference should be 

 made here to the Note on the Evidence concerning the Existence 

 of vein M 4 on p. 651 . ) 



(3) The cross- vein im is never present. This is an important 

 specialisation, seeing that this cross-vein closes the median cell 

 (mc) not only in the rest of the Homoneura, but also in Hetero- 

 neura, and plays its part in the formation of the large basal cell. 

 The loss appears to be due directly to the removal of mf distad, 

 and is therefore to be traced back, like the other specialisations, 

 to reduction in size. 



Tt will be seen from the Table given on p. 650 that the Micio- 

 pteri/gidae are the most archaic family of Lepidoptera still exist- 

 ing, but that they fall far short of possessing the full number of 

 archaic characters exhibited by the Archetype of the Order, as 

 regards the Wing-venation. The Eriocraniidae are somewhat 



