312 ME. H. BOLTON ON INSECT-EEMAIXS FEOM [Sept. IQI?, 



Although I have spoken of the median as consisting of two distinct 

 stems, or as uniting near the bod}* on the missing proximal portion 

 of the wing, the two are united, at no great distance from their 

 points of origin, by an oblique commissural vein which comes off at 

 an acute angle low down on the outer stem, and passes obliquely 

 inwards to the inner one. It has a length of 15 mm. 



The basal portion of the cubitus has been broken away, so that 

 its branching is not readily determinable. 



Enlarged photographs taken with oblique lighting show that 

 the main vein divided low down near its point of origin into two 

 almost equal branches, which curved iirst gradually and then more 

 rapidly to the inner wing-margin, bifurcating twice in each case 

 before the margin was reached. The eight marginal rami of the 

 cubitus thus produced enclose the middle third of the inner wing. 



The anal area is wholly destroyed on the wing itself, and only 

 a trace of one vein can be distinguished on the counterpart. This 

 is a narrow, deeply-sunken vein, which gives off feeble offshoots on 

 both sides, that is, on its outward and inward sides, and diminishes 

 in strength as it passes to the wing-margin, so that the last portion 

 of its course can only be detected with difficulty. The anal area 

 is comparatively small and narrow, and exhibits few veins. 



Affinities. — It will be evident from the foregoing description 

 that the wing is of an unusual type, and possesses several remarkable 

 features. Not only is it one of the largest (if not the largest) 

 wings hitherto found in the British Coal Measures, but the wing- 

 structure in many respects differs from all known forms. 



There is no doubt of its Palseodictyopterous character, but it agrees^ 

 with no known family of that order. The nearest related family is^ 

 that of the Dictyoneuridse, Handlirsch. It does not possess that 

 close, irregular, reticulate venation so characteristic of the genus 

 Dictyoneura, which is the type of the family, but shows instead a- 

 few longitudinal intercalary veins breaking up into widely open 

 polygonal venation. 



The costal and subcostal areas are very narrow, and the outer 

 wing-margin almost straight. The radius is almost furcate near 

 the tip of the wing, while the radial sector is relatively simpler 

 than in Dicti/oneura. It originates far below the middle of the 

 wing, very near the base in fact, and diverges widely from the 

 radius. Xotwithstanding this, positive evidence of only one bifur- 

 cation is to be found, and it is not conceivable that its ultimate 

 branches could have produced more than four terminal twigs. 

 Judging by the course of the subcostal and radial veins, the two> 

 were united for some little distance after their origin. The median 

 had clearly two main stems united by a commissure, the outer 

 stem being much divided in the wing-apex, the inner giving off 

 two branches to the inner wing-margin, and then becoming lost in 

 the intercalary veins. 



The cubitus is a much- branched and widely divergent vein, and^ 

 like the median, is deep-seated. It is unlike the cubitus in any 



