278 



MESOZOIC INSECTS OF QUEENSLAND, vill.. 



Rs is at the same level as the first fork of M, while the fork of Rs is at the same 

 level as the origin of M4. Distance between fork of M1-2 and fork of M3-4 

 2.5 mm.; length of basal piece of M4, 1.2 mm. In the medio-cubital cell, the 



Text-fig. 69. — Mesogeteon affine, n.sp. Venation of base of forewing. (x fi-4). 



remains of the archedictyon consist only of the long vein running from near the 

 base of Cm to the fork of M, together with a vein descending obliquely from it 

 on to m-cu; from near the lower end of this latter vein, a short broken stump 

 runs upwards towards M3-4, but ends half-way across the cell. There is also a 

 weakly formed veinlet running longitudinally in the space between R and M, 

 and ending on Rs just distad from its origin. Cross-ridging very distinct; tuber- 

 culation moderately well preserved. 



Type, Specimen No. 206a, in Coll. Queensland Geol. Survey, Brisbane, Q. 

 Type-counterpart , specimen No. 2066, in same collection. 



Horizon, Upper Triassic, Ipswich, Q. 



Specimen No. 207a was found not far from No. 206, and is shown in Plate 

 XX., fig. 22. Text-fig. 70 shows a drawing of the preserved parts of the venation, 

 with the rest of the wing restored by broken lines. The close resemblance to the 

 venation of the hindwing of a Heteroncurous Jfotli will be at once evident. I 

 was for a long time in doubt as to whether this wing did not really belong to the 

 Lepidoptera. The absence of any portion of the termen, from whicli it might be 

 determined whether a coriaceous border was present or not. made the problem a 

 dilTicult one. But finally a portion of the border was discovered in another 

 closely similar hindwing (No. 97). This discovery made it certain tliat both 

 specimens No. 97 and No. 207a were hindwings belonging to the genus Meso- 

 gereon. Specimen No. 207a is here considered to be the hindwing of M. affine, 

 as it was found so dose to the forewing of that species. 



Comparing the hindwing with the fore, it will be seen at once, from the more 

 normal positions of Sc and R, that the hindwing was considerably broader than 

 the fore in comparison with its length. The preservation of part of the distal 

 border in No. 97 enables us to estimate very closely the actual shapes of these 

 wings, which arc then seen to bear very much the same relationship to the fore- 

 wings that those of a recent Cicadid do to their corresponding forewings. Rs 

 arises a little beyond one-third of the wing-length, and runs oblicjuely downwards 



