HYPERMEGETHID^E. 31 



nearly straight. The tip of the wing is acute. The costal and subcostal veins are 

 not seen. The radius is represented by a single forked vein, not shown in the 

 figures. The radial sector is unbranched until well beyond the middle of the wing, 

 beyond which it gives off four (possibly five) backward branches, which occupy 

 the greater part of the tip of the wing and a portion of the distal inner margin. 



The median is represented by two branches, the outer dividing into two twigs 

 and the inner into three. 



The marginal area occupied by the median is a little longer than that of the 

 radial sector, and the two extend over the distal half of the inner wing-margin. 



The cubitus is a relatively short and stout vein, dividing into two main 

 branches, the foremost having two twigs, and the hinder dividing into four by a 

 double bifurcation. Owing to the wide divergence of its branches the cubital 

 area is larger than that of the median. The anal area was large, but the whole 

 surface has been pitted by attempts to clear the matrix, and as a result the 

 presence and character of the veins cannot be distinguished with certainty. It is 

 possible that certain surface-indications are evidence of two simple widely 

 separated veins. The wing-surface exhibits a strong plication. 



Viewed obliquely, the wing shows a series of ridges formed by the vein with 

 V-shaped intervening sulci, which only flatten out close to the wing-margin. 

 Springing from the principal veins is a close series of fine cross-nervures, obliquely 

 disposed in the direction of the wing-margin. The portion of the wing preserved 

 is sufficient to indicate that as a whole it was triangular in outline. 



Family HTPERMEGETHID^E, Handlirsch. 



1906. Handlirsch, Proc. U.S. National Museum, vol. xxix, p. 672. 



Costa marginal, costal area broad ; radius simple, radial sector present ; the 

 median probably dividing at the base into two or more main branches, the first 

 of which may become united to the radius. Cubitus forked near the base, with its 

 branches widely spaced. Anal veins few, and anal area not exceeding one-third 

 of the inner margin. 



Handlirsch established this family for the inclusion of a gigantic wing of which 

 only the basal half is known. The total length of the whole wing was estimated 

 to be 120 mm., the basal half having a length of 60 mm. The discovery in the 

 Coal Measures of Durham of a nearly similar wing adds to our knowledge of the 

 group, and enables the family to be defined with more accuracy than was at first 



possible. 



The general assemblage of characters found in the Hypermegethidae is, I 

 believe, highly suggestive of the Protodonata, but no definite conclusions can be 

 formulated until the whole wing is known. 



