BY R. J. TILLYARD. 283 



strong ridges, Cu2 aud So lying in deep furrows. This shows that the impression 

 is the obverse or east of a right forewing. Unfortunatelj' the reverse was lost, 

 although a careful search was made for it. 



Type, Specimen No. P. 2 in Mr. John Mitchell's Collection. 



Horizon. — Upper Permian of Belmont, N.S.W. 



At first sight, this wing appears to be nothing more than a slight smudge 

 on the rock surface, and it is only with the aid of a lens of considerable power 

 that the perfection of the venation can be made out. 



This is the first Sternorrhynchous wing discovered at Belmont. The other 

 known Sternorrhynchous wing from the Upper Permian Beds of New South 

 Wales is Lophioneura ustulata Till., recently described from Merewether Beach, 

 near Newcastle (These Proceedings, xlvi., pt. 4, 1921, p. 420), and therefore 

 probably somewhat older in geologic time than the present species. A compari- 

 son of the two wings shows considerable differences, suflScient, in my opinion, 

 to justify the formation of a separate family for each. In Lophioneura, the 

 costal area is wide and short, Sc ending up well before half-way along the costa, 

 Ri ending up a little beyond half-way, and the whole shape of the wing being 

 widely different from that of Pincomb.ea. Lophioneura has Rs forked, M also 

 only once forked. Cm with a very weak distal fork, and the clavus very short, 

 excessively narrow, and without any anal veins upon it; there are also no cross- 

 veins. Both wings are very primitive, for Sternorrhynchous types, in having 

 the veins M and Cui arising from the principal vein so close to the base. But, 

 whereas in Lophioneura the three veins Cui, M and Rs come off: from the prin- 

 cipal vein separately in order, from the base outwards, at short intervals, in 

 Pincombea Cui and M come off at the same point, with Rs arising much further 

 distad from Ri. 



The simple Rs and three-branched M of Pincombea can be paralleled in many 

 present-day Aphiidae. This latter family could certainly be derived from the 

 Pincombeidae by the fusion of Sc with R, together with very strong distal move- 

 ment of all the veins coming off from the principal vein, general narrowing of 

 the wing, and especially strong narrowing of the basal portion, leading to com- 

 plete elimination of any distinct clavus and anal veins. These immense differ- 

 ences only show us how much older Pincombea is than any existing Sternorrhyn- 

 chous type. 



A more useful comparison may perhaps be made with the incomplete fore- 

 wing which I have named Triassopsylla pleeioides, from the Upper Triassie 

 Wianamatta Shale Beds of Glenlee, N.S.W. (These Proceeding's, xlii., pt. 4, 1917 

 (1918), p. 754). Though only the distal half of this wing is preserved, it 

 agrees with Pincombea in having M forked in almost exactly the same way, in 

 having Rs simple, and Sc running very close to R. It differs in having Ri dis- 

 tally forked, the apical border of the wing more evenly rounded, and two cross- 

 veins between Ri and Rs, while the cross-vein between Rs and M, though pre- 

 sent, is more basally placed than in Pincombea. Triassopsylla pleeioides was 

 placed by me, with some doubt, in the family Fsyllidae. Until we know the 

 venation of the basal half of the wing, that doubt must remain; but it is at 

 any rate significant that the distal portions of the two wing's show so much 

 similarity. 



In the perfection of the clavus, Pincombea is certainly the most generalised 

 Sternorrhynchous type yet discovered, and in its general structure it stands 

 closer to the Auebenorrhyncha than any other known type, and serves to bridge 

 over partially the wide gap which now separates the two main divisions of the 

 Homoptera. 



