I'.Y R. J. TILLYARD. Oil 



eosta was evidently a strongly forked vein in the Archetype of 

 the Complex. 



Seetion xi. The Venation of the Paratrichoptera. 



(Text-fig. 65.) 



J n this Order 1 have recently placed four remarkable genera 

 from the Upper Trias of Ipswich, Q., viz. Mesopsyche, Triasso- 

 psyche, Aiistopsyche, and Neuropsyche, described by nie in two 

 previous papers (5, 28). At first sight these wings appear to 

 belong to the Triehoptera ; but a closer analysis shows that they 

 do not belong to that Order at all, and are much more closely 

 related to the Mecoptera and Diptera. 



To these tour genera I now wisli to add the genus Mesopanor- 

 podes, originally described by me under the name Mesopanorpa, 

 from the Wianamatta Shale of Glenlee, N.S.W., and probably 

 of, very much the same age as the Ipswich fossils ((i. pp. 746-7). 

 The name Mesopanorpa being preoccupied, I changed it to Meso- 

 panorpodes* Originally, I considered this fossil to be an aber- 

 rant member of the Order Mecoptera. But it is now apparent 

 that it will go best into the Paratrichoptera, with which it agrees 

 in every particular, except for the possession of a somewhat 

 larger number of cross-veins than are to be found in the Ipswich 

 genera. We may note especially the presence of two cross- 

 veins in this genus between R 2 and R 3) as in Neuropvijehe, and 

 between H and R 5) as in Mesopsyche. The base of the wing 

 appears to be more narrowed in Mesopanurpodes than it is in 

 any of the Ipswich genera. Both in this respect, and in pos- 

 sessing the submedian cross-vein (sm) present also in Protoplasm 

 (Text-fig. 67), amongst the Diptera, Mesopanorpodes is perhaps 

 the nearest Paratriehopterous type yet discovered to the true 

 Diptera. 



The archetypic forewing of the Order Paratrichoptera, as 

 shown in Text-fig. 65, has been constructed by selecting all the 

 lun-t archaic characters exhibited by the five genera already 

 named, and incorporating them into one wing-type. The most 

 complete wings are those of Aiistopsyche (28, p. 202), and 

 Mesnpmiorpudes (6, p. 746) ; these genera have, therefore, played 

 the greatest part in the formation of the Archetype. Aristo- 

 psycht is the only genus of the five in which a basal branch of 



'These Proceedings, xliii., pt. 3, 1918, p. 435. 



