64 FOSSIL INSECTS OF THE BRITISH COAL MEASURES. 



Horizon and Locality. Middle Coal Measures (binds between the " Brooch " 

 and " Thick " coals) ; Coseley, Staffs. 



Description. The fossil is contained in a brown ironstone nodule, the whole 

 wing having a length of 21 mm., and a maximum diameter of 4 mm. It is 

 membranous, and oblanceolate in shape. The outer wing-margin, of which only 

 the distal half is preserved, is flatly convex and curves inwards, meeting the inner 

 margin in a rounded apical angle. The inner margin is feebly concave. The wing 

 has three longitudinal folds, and the extreme tenuity of the integument is accom- 

 panied by a corresponding thinness of the veins. The greater portion of the costa 

 and the whole of the subcosta are missing. The outer portion of the radius is present. 

 It is parallel with the outer margin, and curves round into the wing-apex. The 

 radial sector is parallel with the subcosta, and curving round into the apex is lost, 

 by reason of its tenuity. Lying inward to the main stem of the radial sector in 

 the distal half of the wing are two long veins, and traces of two others, all 

 following the same course, and curving to the inner margin. The two long veins 



FIG. 17.- Brodia priscotincta, Scudder, forma juvenis, Bolton ; diagram of wing-neuration, two-and-a- 

 half times natural size. Middle Coal Measures (binds between the "Brooch" and "Thick" 

 coals) ; Coseley, Staffordshire. Johnson Collection, Brit. Mus. (no. I. 1563) Lettering as in 

 Text-figure 16, p. 62. 



appear to arise from the radial sector, in which case the two of which traces only 

 are seen would do so also. The radial sector therefore seems to give origin to 

 four inwardly directed parallel branches. The whole course of the next vein is 

 not clearly determinable. It passes to just beyond the middle of the inner margin, 

 in an almost straight oblique course, and gives off a single forked outer branch 

 parallel with the fourth branch of the radial sector. This vein can only be the 

 median. The next vein is the cubitus. It is undivided, and goes to the middle of 

 the inner margin. Anal veins are only indicated by feeble traces of a single 

 undivided vein, which apparently reached the margin midway between the cubitus 

 and the base of the wing. 



Another similar wing from the same horizon and locality in the British Museum 

 (no. I. 1564) is 17 mm. long and 5 mm. wide, and lies on the surface of a split 

 nodule of dark-brown ironstone. The wing-membrane is very thin, and forms a 

 slight glaze on the otherwise granulated surface a feature which has made the 

 details of structure difficult to determine. The costa is marginal, the outer margin 

 convex, and gradually curving into the rounded apex of the wing. The inner 

 margin is slightly convex distally, and straight proximally. 



The subcosta is a feeble vein whose course cannot be traced with certainty 



