1<>2 FOSSIL INSECTS OF THE BRITISH COAL MEASURES. 



back. The central area lias a deep median furrow, and is marked off from the 

 lateral halves by two ridges (representing the furrows on the dorsal surface). 

 These ridges converge anteriorly and almost meet. The inner surface is slightly 

 concave, and indented by three faint furrows on each side, parallel with which are 

 traces of fine striatums. 



The mesonotum is 4'5 mm. long, and much wider anteriorly than posteriorly. 

 It is convex, and the hinder border has a raised rounded edge. It is strongly 

 chitinous, much more so than the metanotum, which is crushed down beneath the 

 anal areas of the tegmina, only a little of the hinder portion of the left side 

 showing at one point where the anal areas of the wings have been broken away. 

 The right tegmen lies in the position of rest, its inner margin being in line with 

 the axial line of the body. The left tegmen was rotated outwards to a slight 

 degree before entombment — a feature which, combined with the breaking away of 

 its distal third, has enabled the left hind- wing to be better shown. The right 

 tegmen has a length of 33 mm. and a breadth of 13 mm. 



The costal margin is moderately thickened, convex, and merges gradually into 

 the wing-apex, the latter bluntly rounded. 



The subcostal vein is thin, and encloses a long strap-shaped area, crossed by 

 9 — 10 oblique branches, most of them forking twice before reaching the margin. 



The radius is a strong vein, nearly parallel with the subeosta, and ending on 

 the outer margin in four small branches, the second only forking. The radial 

 sector arises just before the middle of the wing, diverging but slightly from the 

 radius. It gives off three short outward branches to the apex. 



The main stem of the median passes along the middle line of the wing for some 

 distance, and curves inwards to the distal end of the inner margin. The first 

 outward branch arises a little beyond the middle of the wing, and forks into two 

 equal-sized twigs; the remaining two branches remain undivided to the broken 

 n\^v of the wing. The median and its subdivisions occupy the centre and inner 

 half of the wing- apex. 



In the left tegmen the second branch of the median forks. The cubitus is 

 strongly convex in the proximal two-thirds, and bends forwards in the distal 

 third and inwards again to the inner margin. It gives off six inward branches, 

 the fourth and fifth forking before reaching the margin. The anal veins are eight 

 in number, three being very small and short. The first forks twice, and the 

 second once. The inner margin is almost straight. The interstitial neuration is 

 made up of straight nervures. The surface of the tegmina is chitinous. 



The hind-wings appear not only to have been covered by the tegmina, when 

 they were in a position of rest on the body, but to have stretched a little beyond 

 them like a fringe. 



The left hind-wing is thin and membranous, and marked by numerous veins, 

 i lie bases still hidden under the tegmen. A little of the distal portion of the 



