16 



Hemisphere,* and the Locustoidea of the present day. Some of the 

 species figured by Handlirsch resemble fairly closely the hindwing 

 of the species here described. The question of the advance in teg- 

 mination in the forewing is a difficult one. Wherever the substance 

 of the wing is not completely destroyed, as in the present case, but 

 replaced by an inorganic deposit, the relative thickness of fore and 

 hind wings can be fairly well gauged. There can be little hesitation, 

 in the present case, in correlating the advance from an unspeciahsed 

 hyaline wing towards a true tegmeii with the retention of an originally 

 1 palseodictyopterous" condition of the venation, or else with the 

 elaboration of such a condition from an earlier simpler venation. 

 The question, therefore, arises whether some of the Carboniferous 

 Palaeodictyopterous wings were semi-tegminous, and whether we 

 may not soon expect to complete a chain of phylogenetic evidence 

 connecting some of our recent Orthoptera with Palaeozoic forms 

 placed by Haiidlirsch outside this order. 



Genus MESOMANTIDION, gen. nov. 



Wing large, elongate, with strong radius and media. A weak 

 costal vein reaches the anterior border quite close to the base, cutting 

 off a narrow precostal area intersected by a few simple cross-veins. 

 Subcosta is slender but long. Radius is strong, nearly straight, sup- 

 porting above it a large subcostal area narrowest at base and crossed 

 by numerous irregular cross-veins, obliquely placed, and sometimes 

 irregularly branched. No radial sector present, unless distally from 

 the preserved part of the wing. Media is a strong branching vein, 

 the main stem (M2) apparently giving off both an anterior branch 

 (Ml) and a posterior branch (M3) at about the same level, i.e., a 

 little beyond the level of the eiicling-up of C. Both Ml and M2 are 

 again branched further distally. Three slender veins below M appear 

 to represent the cubitus and analis. Cross-veins in single rows only. 



TYPE : Mesomantidion queenslandicum, sp. nov. 



MESOMANTIDION QUEENSLANDICUM, sp. nov. 



Plate 5, fig. 2. 



The fragment la represents the basal half, or perhaps a little 

 more than half, of a rather large wing. It shows the very peculiar 

 convexly curved anterior border still preserved in certain recent 

 Mantoids, such as Metalleutica, and appears to lie not far from the 

 direct ancestral line of that peculiar group. The most remarkable 

 points in the wing are the presence of a separate precostal area, the 



..it. 



