306 S. H. SCUDDER ON THE 



in M. pennsylvanicum. It commences to divide at the same point, but instead of two or 

 three simple interior branches with a tolerably good expansion it forks narrowly in a longi- 

 tudinal fashion, and each of its forks simultaneously divide in a similar way a little further 

 on. Below this the wing is not well preserved, but the veins that do show do not appear 

 to differ from the type. 



The second additional specimen, No. 2022 d,«coiues from a different locality, the Empire 

 Mine at Wilkesbarre, Penn.,anl was found at the horizon of the E. vein on a piece of gray 

 shale tilled with remains of ferns, etc. This specimen, excepting in the internomedian 

 area, preserves also no part not found in 2022 a r ; it is of the same size as it, measuring fully 

 13 mm. in width at the same point; the basal half of the costal border (excepting the 

 humeral angle) and a fragment of the inner margin beyond the anal furrow are preserved; 

 the costal margin is represented as perhaps too convex in the figure, where it should cor- 

 respond very closely to 2022 a. The veins of the mediastinal area are better preserved 

 than there and resemble their disposition more closely than that of No. 2022 b, c, being 

 compound or two-forked away from the base, while in 2022 b, c, they are all simple ; they 

 diverge from one another more widely than in 2022 a, and those toward the humeral angle 

 are simple, distant and incomplete. The scapular vein agrees very closely with its disposi- 

 tion in 2022 b,c, differing only in having an additional branch in the same space, in which 

 it agrees more closely with 2022 a, and in having the axillary branch simply forked inste d 

 of compound. The externomedian vein does not agree with either of the ot'.ier sp jcimen s ; 

 its main stem runs closely parallel to the scapular and has only one branch, which is 

 emitted in a similar position to that of the first branch in the others; this branch, however, 

 is compound, its upper fork dividing, and the whole area which it appears to occupy, in 

 the lost part of the wing, as broad as in 2022 a. The internomedian area appears to be 

 exactly as in 2022 a, but as a general thing only the terminations, while in 2022 a only the 

 bases, of the veins can be seen ; the fragment of the inner border at their tips is straight. 

 The anal furrow appears to be more gently and regularly curved than in 2022 a, but the 

 difference is slight. No anal veins are preserved. 



The differences between these specimens, although considerable, do not seem to be more 

 than individual and strengthen rather than weaken the validity of the other species of the 

 genus, and support the distinctions upon which they have been separated from one another. 



This species, peculiar for the excessive crowding of the veins in the anal area, falls in its 

 general features between 31. pennsylvanicum and 31. anthracophilum. From the latter it 

 differs in that the veins do not curve downward at the extreme base of the wing, but have a 

 sinuous course, the greatest curve being nearly as far out as the middle of the anal area ; in 

 the simplicity of the scapular veinlets and the composite character of the first branch ; and 

 in the crowded condition of the anal veins in contrast to the comparative openness of the 

 neuration elsewhere, nearly all the nervules being long and simple, while in 31. anthraco- 

 philum nearly all are forked about the middle. From M. pennsylvanicum, which comes 

 from the same general locality, it differs in its more tapering form, due to a greater con- 

 vexity of the costal margin ; in the straighter course of the scapular vein, the more gentle 

 sweep of the anal furrow allowing a much narrower space for median veins, which in 31. 

 pennsylvanicum first divaricate at the same point, but here, notwithstanding the narrowness 



