SPILAPTERA SUTCLIFFEI. 55 



The radius is strong, standing up above the surface, and almost parallel with 

 the subcosta. The radial sector arises from the radius at about 22 mm. from the 

 base of the wing 1 . The median vein, owing to its inward direction away from 

 the radial sector, is better shown. It forks very low down into two equal 

 branches, both of which are widely spaced. The outer branch divides almost 

 opposite the point of origin of the radial sector, while the inner branch forks 

 much nearer the base of the wing, the innermost branch curving sharply 

 back from its fellow, so that the area between them is wide almost from the 

 commencement. 



The general direction of the branches of the median is such that they would 

 reach the outer half of the inner margin of the wing. 



The cubitus consists of two main stems, the basal union being missing; the 

 outer branch passes, after twice forking, in a double curve down to the inner 

 margin of the wing, the inner branch being directed more directly backwards, 

 and forking three times in the basal third. Fragments of four anal veins are 

 distinguishable, the first dividing near the middle of its length into two equal 

 branches. The interstitial neuration seems to have consisted of comparatively few 

 straight and well-spaced nervures, some of which can be seen crossing the wide 

 area between the innermost twig of the median and its fellow. No others are 

 visible, except those in the intercostal area already mentioned. 



Affinities. — Notwithstanding the fact that only about one-third of the wing- 

 is known, it is yet possible to determine the generic characters with a reasonable 

 degree of accuracy. The mode of division of the radius and median, the manifest 

 importance of the latter, the wide area between the median and cubitus, and the 

 few widely spaced cross-nervures, are all typical Spilapteroid characters. The 

 wing cannot be confused with that of Stenodictya, in which the median is much less 

 developed, and the interstitial neuration closely reticulated. The only other genus 

 to which it might be referred, that of Becquerelia, is distinguished by a union of 

 the anal veins, which in Spilaptera and in this specimen are distinct. 



Spilaptera has hitherto comprised only three species. From S. pacJeardi, 

 Brong., the specimen differs by the subcosta being parallel with the outer margin ; 

 by the equal separation of the subcosta, radius and median in the basal third of 

 the wing ; and by the division of the median into two branches close to the base of 

 the wing. 8. libelhdoides, Brong., of which the distal half of the wing only is 

 known, has a much feebler cubitus, which divides by forking further out than in 

 8. sutcliffei. S. venusta, Brong., was established on a fragment much similar to that 

 of S. libelluloides, in which the subcosta is a short vein, and the radial sector arises 

 nearer the middle of the wing. 



