BY R. J. TILLYARD. 129 



based upon the former character, and an entirely misleading 

 specific name, neither of which can be altered. 



Sycopteron symmetricum Bolton. (Text-fig. 3, 6, c). 



Sycopferon symmetrica Bolton, oj). cif., pp.6 8, PI. ii., figs. 1-2. 



If this fossil could be proved to be Mecopterous, it would be 

 one of the most striking discoveries in Pal?Poentomology. For 

 that reason alone, we are all the more bound to examine the 

 evidences of its supposed Mecopterous affinities as carefully as 

 possible. 



Text-fig.3, b, c, are portions of Bolton's PI. ii., fig. 2, which, as 

 far as I can see by comparison with the photograph in his fig. 1, 

 is accurate in all except a possible minor detail or two. The first 

 thing that strikes one, on examining this fossil, is the way that 

 its wings are folded down the back of its abdomen. If this were 

 the natural position of rest, it would be that of a Dipteron or a 

 Hymenopteron; yet both these Orders are excluded from the 

 question, for reasons that must be sufficiently obvious- without 

 stating them. We have, then, to conclude, either that SycojJteron 

 belonged to some extinct Order, which folded its wings in this 

 position (a highly improbable theory), or that it belonged to some 

 Order in which the wings were held roof -like over the abdomen; 

 in which case, the flattening down of the wings in the fossil 

 may well have caused some underfolding of either the costal or 

 the posterior border of the wings, or both. 



Bolton claims for his insect a Panorpoid venation, stating that 

 its nearest approach is to be found in Orthophlehia of the Lias. 

 When, however, he goes into detail, it is quite clear that he is 

 unable to homologise the separate veins of Sycopteron with those 

 of Orthop)}dehia^ without getting into very serious difficulties. In 

 order to show this, I give in Text-fig.3, «, 6, the venation of 

 Sycojiteron, (h), as interpreted by Bolton, and the venation of 

 Permochorista, (a), which is the oldest fossil Mecopteron known, 

 and the venation of which closely resembles that of Orthophlehia. 

 It will be seen at once that the type of venation present in the 

 Mecoptera (and there is no Order in which the venation is more 



