BY R. J. TILLYARD. 



431 



On the above suppositions, we may restore the two wings as 

 shown in Plate xlv., fios.13-14, the missing portion of each wing 

 being made approximately the same as the corresponding portion 

 present in the other. 



The total length of the wings, as restored above, would be 

 about 46 mm. each. If, then, the insect were of slender build, 

 with a narrow thorax, the total expanse of the wings must have 

 been about 96 nnw., or nearly four inches. This is very small for 

 a Protodonate; but the fossil beai's the marks of a reduced type. 



Affinities of the Fossil. 



This fossil is certainly one of the most puzzling of all the 

 Ipswich Insects. As far as I know, there is nothing in the 

 whole range of insect- venation, either fossil or recent, that shows 

 any close relationship to it. In finally determining to place it 

 in a new Suborder within the Protodonata, the following points 

 have weighed w^ith me: 



(1). The differences in the branchings of the media, in the two 

 wings preserved, are suflicient proof that we have a fore- and a 

 hindwing preserved, not two forewings or two hindwings. 



(2). Which wing is the fore and which is the hind, is nof 

 capable of absolute proof. But, unless the insect is altogether 

 twisted out of shape, the more anterior one should be the fore- 

 wing, as I have assumed it to be. 



(3). The close similarity evident between fore- and hindwing 

 in venation, as well as in shape, puts several Orders out of court at 

 once; notably the Orthoptera, the Perlaria, and the Homoptera."*^ 



(4). In considering the type of venation exhibited, there would 

 appear to be characters belonging to three Orders, viz., the Pro- 

 todonata, Planipennia, and Mecoptera. These characters had 

 to be carefully weighed, with reference to known types of each 

 Order. 



" We might note here the existence, in Australia, of Homoptera belong- 

 ing to the subfaniil}' Derhiiice of the family Fit/goridce, with the forewing 

 narrowly elongate as in Acroplana; also, a similar elongation occurs in 

 both wings in the genus StenobieUa of the family Tt-icJiomatidcf, in the 

 Order Planipennia. 



