BY R. J. TlLLYARD. 743 



lished, Mr. Walk om sums up the evidence as follows: — "The 

 Ipswich Series must be regarded as Triassic, perhaps homo- 

 taxial with the so-called Ehsetic Beds of various areas, but pos- 

 sibly older." 



Descriptions of the Specimens. 

 Order PROTORTHOPTERA. 



Genus Notoblattites Tillyard. 



Originally, I placed this genus in the Order Blattoidea. How- 

 ever, its wing- venation shows it to belong to Handlirsch's Order 

 Protorthoptera, to which I now remove it. But it should be 

 noted that the fossils of this genus preserved m the resting- 

 posiiion show us that it carried the tegmina folded flat along the 

 back, as in the true Cockroaches; the hindwings being folded 

 beneath tliem, and projecting a little beyond them. This shows, 

 I think, that the Cockroaclies do not really belong to a separate 

 Order, but are a specialisation from a very ancient Protorthop- 

 terous type, the anal area of the tegmen becoming developed into 

 a specialised convex clavus; whereas, in JS' otohhittites and other 

 insects placed in the Protorthoptera, the wing-venation remained 

 more primitive, with no specialisation of the anal area. 



Notoblattites shows us that the typical resting-position of the 

 Cockroaches was assumed before the specialisation of the tegmen 

 set in. This resting-position is a specialisation from an origijial, 

 flattened, roof-shaped position of holding the wings, which has 

 become accentuated in most recent Orthoptera. It can be 

 paralleled by the development of the same process in the Diptera, 

 from a similar roof-sliaped position of the wings in the ancestral 

 Order Mecoptera. 



The type of this genus is the large wing, Notoblattites subcos- 

 talis Tillyard, from the Wianamatta beds of St. Peter's, near 

 Sydney. Two fragments of very fine wings, closely allied to 

 this, are here described as new species. 



Notoblattites wianamattensis, n.sp. (Text-fig. 8). 

 Greatest lenyth offraym iit, 28 mm., (measured from base of Sc 

 to the distal broken end of C). The specimen shows the basal 



