218 SCUDDEK ON THE CARBONIFEROUS 



which lies this vein. The anal vein is not crowded against those above it; it has a curve 

 even more sweeping than, but running subparallel to, the internomedian vein, and emits 

 several similarly curving branches, of which fragment-' of two can be seen upon the stone ; 

 at base it is separated from the veins above by a space several times its own width, and 

 at the extreme base it seems to part more widely from them, and to have its root attach- 

 ments at a considerable remove from them ; the vein itself is neither depressed nor 

 elevated. 



The cross-veins of the wing are very conspicuous, especially in the two broad upper 

 • interspaces ; here they are prominent, in relief, generally simple, occasionally forking, 

 and then rather widely, generally curved or sinuous, subequidistant, and dividing the inter- 

 spaces into cells generally about twice as broad as long. In the mediastino-scapular 

 interspace they are generally regularly curved with the convexity outward ; and the same 

 is usually the case with the other cross- veins of the interspaces below, in all of which they 

 are found (even in the slender interspace between the scapular and the upper branch of the 

 externomedian vein) ; though here they are much feebler, more numerous, uniform and 

 simple ; they are especially feeble and numerous in the internomedio-anal intersj)ace, as 

 well as in the slight fragments that remain of the anal area. 



Besides these cross-veins a re a few others, the nature of which it is more difficult to 

 divine ; such are three short, curving, transverse impressions which cross continuously the 

 base of scapular and externomedian veins ; and also a considerable number of transverse 

 impressions on these same veins away from the base generally crossing the vein, sometimes 

 only half crossing it and visually in continuation of the ordinary cross-veins in the inter- 

 space below ; these latter cross-veins are not shown in the figures ; they are not con- 

 spicuous in the fossil and appear to be confined to these two veins. 



In addition to these points it may be mentioned that the only fragment of a border 

 which remains shows that the edge of the wing was spinous ; toward the base the costal 

 margin is furnished on its convex portion (pi. 17, fig. 11) with frequent short, oblique, 

 spinous points, which further out seem to be altered to distant, recumbent, outward 

 directed, longer and rather slender spines. 



Length of the fragment 43 mm. ; breadth 32 mm. ; greatest width of upper interspace 

 10 mm. 



This fragment is remarkable for representing the largest known insect-wing from the 

 paleozoic rocks, not excepting the Acridltes formosus of Goldenberg from Saarbriick, or 

 my Megathentomum pustulatum from Illinois. Certainly not more, probably much less, 

 than the fifth of the wing is preserved (pi. 17, fig. 12), but the direction of the veins, their 

 very great robustness, and the extraordinary distance apart of the upper three, are clear 

 indications that the spread of wing enjoyed by this insect was not less than 25 cm., and 

 may have been even more than 35 cm., while the width could not have been far from 

 6 cm. All the principal veins are a millimeter or more thick. 



The specimen occupies the entire surface of a reddish-brown iron-stone nodule and came 

 from the coal measures near Chesterfield, between Shelton and Clayborne, Derbyshire, Eng- 

 land ; it was received for examination from Rev. P. B. Brodie, to whose collection it belongs. 

 The reverse is in the British Museum, from which I have received excellent casts through 



