862 



MESOZOIC INSECTS OF QUEENSLAND, vii., 



bracidae becoming specialised in the sculpture of the prothorax. 

 The Membracidae are also specialised in certain aspects of their 

 wing-venation, notably in the very distinct narrowing of the 

 clavus, and in the development of a complete distal ambient vein 

 (Text-fig 1 b, amb.), uniting the tips -of R, M and Cu; with a 

 definite clear wing-area, uncrossed by any veins, between it and 

 the wing-margin. Neither of these characters, again, is to be 

 found in any of our fossils; and therefore they are not to be 

 considered as Membracidae. 



Apart from the Ipsviciidae, already mentioned, all the fossil 

 tegmina from Ipswich belong either to the Jassidae, or to some 

 archaic family of Auchenorrhyncha not existing at the present 

 day. The characters of the Jassid tegmen are sufficiently well 

 shown by the genus Eurymela (Text-fig. 1 c) . The clavus is, 

 typically, fairly broad, in the form of an obtuse-angled triangle, 

 separated from the rest of the wing by a very (straight, aud 

 usually deeply impressed, vena dividens (Cugl), and having the 

 veins 1A and 2A lying upon it far apart, vein 2A being fre- 

 quently waved. Sc is absent, or completely fused with R. R 

 and M are fused together basally for some distance. The 

 branchings of these two veins vary considerably, as may be seen 

 by studying a number of different species of the genus Eury- 

 mela. Cuj is a straight, or nearly straight, vein running above 

 and about parallel to Cu 2 , and remaining unbranched until near 

 its distal end. 



Three of the Ipswich fossil tegmina agree with the Jassidae 

 in all these points, and may therefore be placed definitely within 

 that family. These are Mesojassus Till. (8), Triassojassus n.g., 

 and Eurymelidium n.g. 



There still remain over a number of tegmina which cannot 

 be satisfactorily placed in any existing family. We have, there- 

 fore, to consider whether there are any known fossil forms with 

 which they show affinity. The fossil forms already known in 

 the Homoptera, which do not belong to existing families, are 

 the Liassic family Procercopidae of Handlirsch, and the Permian 

 genus Scytinoptera Handlirsch. The venation of the former is 

 that of the true Cercopidae. Handlirsch only placed them in 

 a separate family because he was of opinion that true Cerco- 

 pidae could not have existed in the Lias. They may, therefore, 

 be dismissed from the question. With respect to Scytinoptera, 

 which comes from the Upper Permian of the Kama River, Rus- 



