Vol. 68.] THE MIDLAND AND SOTJTH-EASTERN COAL MEAST7RES. 311 



lend colour to the belief that it has followed a natural line of 

 weakness, the more delicate inner part of the wing breaking awaj 

 from the outer stronger portion. 



The costal, subcostal, radial, and median are all well-developed 

 Teins, stout in structure, and standing out in relief. The first 

 three retain this evidence of strength over two-thirds of the wing, 

 the median vein showing signs of attenuation, beyond the proximal 

 third. The general structure of the wing is indicative of con- 

 siderable powers of flight. The costal margin, of which only a 

 small distal portion is shown, was fairly straight for the greater 

 part of its length. The remnant preserved shows up as a stout, 

 slightly elevated, and well-rounded ridge. 



The subcostal closely follows, and agrees in general character 

 with the costal remnant. It is present, or indicated, over the 

 greater part of its length. It pursues a straight course, giving off 

 a forwardly directed branch 4 mm. from the broken distal end 

 -and. about 25 mm. before reaching the (estimated) tip of the wing. 

 It originates low down near the body, and in contact with the 

 radius. The radius, at a little over 10 mm. beyond its source of 

 origin, divides into two main branches : the outer branch (radius) 

 pursuing an unbranched course parallel to the subcostal, from 

 which it is nowhere separated more than 2 mm. The inner branch 

 {radial sector) diverges widely from the former, the two enclosing 

 a long, narrow, triangular area. At 50 mm. beyond the first 

 forking, the inner branch divides into two equal rami, which open 

 out quickly to a distance of 3 mm., and then pursue an almost 

 parallel course towards the tip of the wing. The direction of the 

 branches of the radial sector is such as to show that they finally 

 ended upon the inner half of the wing-tip, the outer ramus almost 

 certainly forking again before reaching the wing-margin. The 

 radial area is 16 millimetres wide at the broken edge of the wing, its 

 branches showing a divergence sufficiently great to include the 

 greater part of the wing-tip. 



The median vein consists of two branches, the common origin of 

 which is not shown. Up to the middle of the wing the two remain 

 parallel. 



The outer branch of the median attains a length of 66 mm. 

 before branching. It then gives off four branches on its outer 

 side, the last arising quite close to the inner margin, upon which 

 the main stem also ends. The first forward branch continues 

 almost in the line of the stem, following a direction which would 

 bring it out upon the inner margin of the wing-tip. The second, 

 third, and fourth branches pursue a parallel course, the second 

 bifurcating just in front of the broken edge of the wing. 



The inner stem of the median keeps parallel to its fellow for 

 two-thirds of its length. It then gives off a strong backwardly- 

 directed vein to the wing-margin, and at 11 mm. farther out 

 divides into two unequal veins, the outer and feebler disappearing 

 in a small plexus of polygonal reticulation. The inner vein runs 

 -out to the wing-margin parallel to the branch- vein first thrown off. 



Q. J.G.S. No. 271. 2 a 



