BY B. J. TILLYARD. 



631 



and the cross-vein im, as an irregular, transverse zig-zag from 

 the base of the second apical fork to the base of M 1+2 ; and the 

 lower anastomosis, formed by the basal piece of M 3+4) the cross- 

 vein m-cUj and a highly specialised arrangement of the ends of 

 the branches of Cu and the cross-vein icu, as a second irregular, 

 transverse zig-zag line, taking in the base of the fifth apical 



5c Rj R 2 



Text-Fig. 74. 

 Forevving of Chaetopteryx villosa (Fabr.) , after Ulmer, but with letter- 

 ing added, to show the formation of the anastomosis. Lettering as 

 on p. 535. 



fork. The highest stage in this evolution is the alignment of 

 the upper and lower anastomoses to form a single transverse 

 zig-zag line, called simply the anastomosis, running from the 

 fork of R 2+ 3 right across the wing. This is to be seen in such 

 genera as Chilostigma and Chaetopteri/j- (Text-fig. 74). 



The formation of the anastomosis in the family Limnephilidae 

 recalls the analogous formation called by the same name in the 

 Order Perlaria. 



For a comparison of the Archetypes of the Trichoptera and 

 Lepidoptera, see pp. 034-5. 



Section xiv. The Vexation of the Lepidoptkra. 



(Plates xxxii.-xxxv.. figs. 17-24 and Text-figs. 36b, 53-56, 58-59, 



75-103.) 



The venation of the Archetype of this Order is shown in Text- 

 fig. 75, which should be carefully compared with that of the Tri- 

 ehoptera in Text-fig. 71. The following are the chief points to 

 be noted : — 



