606 THE PANORPOID COMPLEX, iii., 



Besides these points, when I founded the Order Paramecop- 

 tera, I emphasised the presence of the complete and beautifully 

 formed cubito-median Y-vein, which is unique in its perfection. 

 The only known Mecopteron in which this Y-vein is present is 

 the Upper Triassic Stereochorista, which I was, therefore in- 

 clined to regard as exceptional for that Order. However, as will 

 now be seen from Section iii., a more complete comparative 

 study of this formation makes it almost certain that this Y-vein 

 was present in all the Orders of the Complex originally. Hence 

 the character may no longer be used for separating the Para- 

 meeoptera from the Mecoptera, and one of the principal differ- 

 ences between the two Orders breaks down. I think it can only 

 be a matter of time before other new fossil types, either from 

 the Permian of Newcastle or from the Trias of Ipswich, will 

 be discovered, in which this Y-vein will be found perfectly 

 formed, though perhaps not quite so prominently as in Bel- 

 mont ia* Ultimately it will, no doubt, be possible to show a 

 series of forms making a complete connection between Belmontia 

 and the true Mecoptera; so that the Paramecoptera may then 

 be merged into the Mecoptera as a separate Suborder. The 

 same will undoubtedly prove to be the case with the Protome- 

 coptera of the Ipswich Trias, dealt with in the next Section, 

 since these are even more like the true Mecoptera than Belmontia 

 is. 



Another distinction to be noted, of less importance, is that 

 the wing of Belmontia was almost certainly more or less pointed, 

 whereas the wings of all true Mecoptera, even those of the very 

 slender-winged Bittacidae, are always well rounded at the tips. 



The points that are of importance in Belmontia, as regards 

 the evolution of the more recent Orders, are as follows: — 



(1) The cubito-median Y-vein. This is fully dealt with under 

 Section iii. 



(2) The distal forking of Cu 1 . Whether this fork originated 

 from an incomplete fusion of M 5 and Ciii distally, or not, it 

 is quite certain that the forked condition is more archaic than 

 the simple straight condition found in the true Mecoptera, the 

 Paratrichoptera, and the Diptera. The forked condition is re- 

 tained in the Trichoptera, Lepidoptera, Megaloptera and the 



'Since this was written, Mr. Mitchell has forwarded me a new Mecop. 

 teron from the Upper Permian of Belmont, N.S.W., in which the cubito- 

 median Y-vein is well formed. E. J. T. 



