BY R. J. TILLVARt). 121 



In Text-fig. 2, c, I have figured the base of the hind wing of 

 Xantholeon helmsi Tillyard, in order to contrast the simphfied 

 condition of this wing with the complicated condition of the fore- 

 wing discussed above. Since the MyrtuphMtntidm are admittedly 

 derived from Nymphid-like ancestors; and since, in the Nymphidce 

 themselves, both the media and the cubitus of the hindwing are 

 already simple, unbranched veins, it must follow that this con. 

 dition is to be found in their derivatives, the Myrmeleontidce. It 

 should, however, be noted that there are signs of specialisation 

 even in the hindwing, in that the vein lA approaches basally 

 very close to Cu, very nearly fusing with it; while 8c and R are 

 completely fused together throughout the basal portion of the 

 wing. 



We have now to consider whether our new discoveries on the 

 structure of the cubitus require us to make any revision in the 

 present classification of the Myrmdeontidiv. Esben-Petersen, in 

 Part iii. of his "Australian Neuroptera,""^ has named the area 

 between Cuj^ + Mo, Cujb, and the hindmargin of the wing, the 

 intermibital area, and has pointed out that a Banksian Line is 

 sometimes developed in this space; such a line, he calls the inter- 

 cubital line. With this I am in agreement. Now the develop- 

 ment of an intercubital line is evidence of high specialisation in 

 this area. Therefore, those genera in which it occurs, if they 

 have hitherto been regarded as primitive, must have their posi- 

 tion reconsidered. In the tribe Creag7^itii, this intercubital line 

 is beautifully developed, and is correlated with a condition of 

 parallelism between Cui^ + Ms and Cujb- It was natural, so long 

 as this latter vein was taken to be Cuo, that this condition of 

 parallelism should be considered primitive. But the archaic 

 condition existing for Cujb is not one of parallelism to Cuja^ + M.,, 

 but rather, as may be seen in Xantholeon, one of strong diver- 

 gence from it, Cujb running obliquely to the margin, and parallel 

 to the numerous branches descending from Cuia-fMa. Xantho- 

 leon^ Gymnocnemia^ Periclystus, and other genera show this 



♦These Proceedings, 1917, xhi., Pt.l, pp.203-219, PI. x.-xv. (PL x., fig. 

 1, Protoplectron striatellum Esb.-Pet. ). 



