122 MR. H. BOLTOX OX A GIAXT DKAGOX-FLY [June 1914,. 



The character of the radius and the media can only, therefore, he 

 assumed by reference to what obtains in the wing of allied Proto- 

 donata, such as Meganeiira monyi and M. selysii. 



In these forms a complex of principal veins arises from one or 

 two roots between the sub-costa and the cubitus. In the case of 

 M. monyi, this complex arises from a relatively-stout radius and 

 a closely-applied very thin media. In M. selysii, it would seem 

 that the complex arises from a joint radius-media trunk. 



The vein-complex occupies almost the whole of the distal two- 

 thirds of the wing in both species of Meganeiira. Of its presence 

 in the Radstock wing-fragment there is no trace, except the detached 

 fragments already mentioned. In the restoration which I have 

 attempted (PL XIX, fig. 3) it will be seen that the vein-fragments 

 appear as parts of the media, the radius being wholly missing. 



Cubitus. — This vein is separated from the sub-costa by an 

 interval formerly occupied by the radius and the media : this 

 interval varies between 5 and 10 mm. The cubitus is a strong 

 flattened vein giving oft* an oblique branch from its hinder border, 

 then curving forwards, and finally backwards as it pursues its 

 course outwards. 



Its general direction is such as to lead to the inference that it 

 curved backwards into the hinder wing-margin, probably reaching 

 it, about the end of the middle third of the wing. The most 

 proximal portion of the vein has been broken away ; its course may 

 probably be indicated by a faint line passing forwards in the 

 direction of the bases of the sub-costa and costa. The outer of the 

 two backward curves of the cubitus is the greater, and so a rela- 

 tively wide interval lies between the cubitus and the hinder margin 

 of the sub-costa. This accords precisely with what obtains in the 

 same region in Meganeiira monyi, and is undoubtedly caused by the 

 beginning of the vein-complex of the radius and media, which lay 

 between the two. 



The oblique proximal branch of the cubitus, to which I have 

 already referred, is a deeply-incised and stout vein which passes 

 backwards until it joins with the anal vein. It has the appearance 

 of an important commissure between the cubitus and the anal, or 

 of a posterior branch of the former which has fused with the 

 latter. 



Beyond the commissure, the cubitus is joined to the anal by a 

 system of parallel slightly-curved branches, similar in character to 

 those which unite the sub-costa with the costa. No fewer than 

 twenty-five of these branches can be distinguished. Inward of 

 the commissure are two similar transverse branches, a little more 

 curved than the remainder. As in the costa and sub-costa, a 

 median line of tubercular ornament is present. 



Anal. — The fourth of the strongly-marked veins is the anal. 

 Its course is somewhat similar to that of the cubitus ; but the 

 proximal backward curve is longer and flatter than in that vein, so 

 that its forward-directed middle portion lies opposite to the second 



