270 



MESOZOIC INSECTS OF QUEENSLAND. 



No. 8. Hemiptera Homoptera (Contd.). The Genus Mesogereon ; with a 

 Discussion op its Relationship with the Jurassic Falaeontinidae. 



By R. J. Tillyard, M.A., Sc.D. (Cantab.), D.Sc. (Sydney), F.L.S., F.E.S., 



Entomologist and Chief of the Biological Department, Cawthron Institute, Nelson, 



N.Z. ; formerly Linnean Macleay Fellow of the Society in Zoology. 



(With Plates xvi. — xxi. and seven Text-figures). 



The genus Mesogereon was first proposed by me (1916, p. 33), for the 

 reception of a fragment of a very remarkable forewing from the Upper Trias of 

 Ipswich, Queensland. The name was chosen because of a certain amount of 

 resemblance between the fragment and the well known Permian fossil Eugereon 

 hoeckiiigi Dohrn (1867), which Handlirsch (1908, p. 389) has placed alone 

 in a new Order Protohemiptera. The name which I gave to this Upper Triassic 

 wing-lragment was Mesogereon neuropunctatum, the specific name being an al- 

 lusion to the remarkable formation of cross-ridges running between the main 

 veins, and interrupted midway by an unridged area carrying strongly marked 

 tubercles or macrotrichial sockets. This formation was interpreted as being 

 that of a series of original cross-veins, or archedictyon, in process of reduction. 

 The condition of the fossil in this respect was held to indicate that it represented 

 an intermediate stage between Handlirsch's Fossil Order Protohemiptera and his 

 Palacolieraiptcra, and a doubt was expressed as to whether two distinct Orders 

 should be maintained. Later evidence obtained from a study of other fossil 

 Heiriipteru has already convinced me (1918) that Handlirsch's Palaeohemiptera 

 should be considered as only a Sub-order of the Order Hemiptera, while the 

 Protohemiptera, as represented by Eugereon, stand out so distinctly that they 

 must certainly be maintained as a good Order. Mesogereon itself was placed 

 by me in the Order Protohemiptera, since it appeared probable, from the vena- 

 tion preserved in the fragnunt, that the complete wing, when discovered, might 

 have a vcnalional scheme not unlike that of Eugereon. 



In the two consignments of Ipswich fossils received by me from Mr. Dunstan 

 since my first paper was written, there is a considerable amount of material 

 belonging to the genus Mesogereon. This includes no less than three forewings, 



